Alouatta pigra). The mother formed part of a group of five individuals inhabiting an anthropogenic setting in the tropical lowlands of southeast Mexico. A total of 7 h and 50 min passed from the rupture of the amniotic sac early in the day to the crowning of the infant from the birth canal. The delivery of the infant lasted ~ 3 min. We describe the event while referencing images and time points in a supplementary video recording. We place our findings in the context of the available reports of live births in the Alouatta genus, time of day, birth duration, and group activity budget on the day of the birth. While primates tend to give birth at night to reduce complications from group interactions, the observed birth took place during the day, which may have been possible due to an alteration in group time allocation. Our report provides in-depth details of the events of a birth and important information regarding the natural history of the black howler monkey.We present the first description of a diurnal live birth of a wild black howler monkey (The online version contains supplementary material available at 10.1007/s10329-022-01022-z. Alouatta) are an example of primates with these factors, including an estimated gestation period ranging from 152 to 195 days and an interbirth interval of 16–23 months  in an anthropogenic setting in Chiapas, Mexico. We place our findings in context with available reports of live births from the Alouatta genus  plantation (~ 11 ha) and the grounds of a hotel (~ 2 ha). Native  and non-native  vegetation within and around the borders of the plantation served as food resources for the black howler monkey group. A vegetation survey based on ten 50-m transects (0.1 ha) revealed that the average diameter at breast height (DBH) in the fragment was 37.1 ± 26.5, while the tree height was 13.6 ± 6 m  located in the anthropogenic landscape outside of Palenque National Park (PNP) in Chiapas, Mexico. Annual temperature in Palenque ranges from 20 to 32 °C CONAGUA . Mean anWe registered the birth while conducting a study regarding the influences of vegetation structure present in degraded habitats on the patterns of movement, diet, and activity of black howler monkeys , we began recording photos and videos of the major events during the birth. Since we stopped recording every time the mother went out of sight, the supplementary video contains short recordings compiled in a continuous series. We reference specific moments in the footage with descriptions and the actual hour of the day for each major event of the birth process. Therefore, the references to time durations in the supplementary video do not reflect the actual duration of the birth. Human presence other than the observers was common on the hotel grounds, and one onlooker can be heard on the video recording clapping and exclaiming during the birth of the infant.We found the mother, a multiparous female, with her group on the morning (09:27 h) of May 18, 2019. Upon locating the group, we noticed a yellow and glossy amniotic sac coming out of the genitals of the mother  with exposed lower branches. At 17:44 h, 7 h and 50 min after the amniotic sac ruptured, the mother started pacing on the tree branches, and we saw for the first time the head of the infant crowning , the group huddled close to the mother again, 12 m high in a mango tree , they rested for 70% of the time, fed for 16.6%, moved for 2.3%, vocalized for 1%, had social interactions for 3.6%, and traveled for 6%. Their travel distance on the day of the birth was 41 m.We made notes during the following observation day on May 19, including a completely severed umbilical cord and much less moisture present on the infant and mother. We did not witness the mother consuming the placenta or find it on the ground the next day Below is the link to the electronic supplementary material.


This study aims to investigate the association between paternal methylenetetrahydrofolate reductase (MTHFR) polymorphisms (C677T) and embryonic development, pregnancy, and neonatal outcomes in intracytoplasmic sperm injection (ICSI) treatment.A total of 191 infertile men undergoing ICSI treatment at the Reproductive and Genetic Hospital, The First Affiliated Hospital of USTC, were recruited between January 2020 and June 2021. The MTHFR C677T polymorphism genotyping was evaluated in these male patients, and they were stratified into three groups according to genotyping results: Control (CC), heterozygote mutated (CT), and mutated homozygote (TT). In addition, we conducted a comparative analysis of embryonic development, pregnancy, and neonatal outcomes among these three groups.p = 0.37), high-quality embryo rate , blastocyst formation rate , implantation rate , and clinical pregnancy rate  were not comparable among these three groups. Moreover, no significant difference was observed in terms of pregnancy outcomes  and live birth rate ). Additionally, no marked difference was observed in terms of neonatal outcome , birth height (p = 0.75), birth weight (p = 0.35), neonatal sex (p = 0.48), gestational age at delivery (p = 0.24), Apgar score (p = 0.34), and birth defects  among the study groups.The embryonic development (including normal fertilization rate (80.14% vs. 83.06% vs. 85.10%; The paternal MTHFR C677T polymorphism is not associated with embryo quality, pregnancy, or neonatal outcomes in ICSI treatment. Therefore, in our population, MTHFR polymorphisms do not provide helpful information in explaining ICSI failure. Howevere births . Underste births . ICSI pre births . Previoue births –6. Accore births , implyinvia the methionine synthesis pathway  guidelines for semen analysis . Sperm concentration, progressive motility, and total motility were assessed by computer-assisted sperm analysis (CASA) under a phase-contrast microscope  equipped with a SAS-II system . Sperm morphology was evaluated through Diff-Quick staining  at ×100 magnification under a light microscope . Leukocytes were stained with benzidine for the peroxidase test (Ankebio). Antisperm antibody (AsA) levels were measured by the mixed antiglobulin reaction (MAR) method (Ankebio). Sperm DNA fragmentation was evaluated by flow cytometry according to the manufacturer’s protocol .The whole genome DNA was extracted using QIAquick PCR purification kits  from the blood samples of the male patients. The MTHFR C677T genotype was analyzed using a fluorescence PCR detection kit (PCR-fluorescence probe) produced by Tailored Medical . Fluorescence PCR detection was conducted under the following conditions: a 4-μl whole genome DNA and a 10-μl PCR reaction system. Next, the manufacturer recommends 95°C denaturation for 15 s and 60°C annealing/extension for 60 s, with 45-cycle reaction conditions. After the PCR reaction, the endpoint fluorescence in each sample well was measured using the ABI 7500 fluorescence quantitative PCR instrument , and the MTHFR genotyping results were accurately determined using the ABI 3730 Genetic Analyzer .in vitro fertilization (IVF) PLUS medium (Vitrolife). Embryos were cultured in a G-1 medium (Vitrolife) in a desktop incubator  for at least 3 days. Progesterone was used for luteal support.ICSI was conducted as previously described . The womvia two blood hCG tests conducted 14 days after transplantation. An ultrasound screening was performed 30 days after transplantation to detect visible sacs and to evaluate their development.Clinical pregnancy was confirmed p < 0.05 was regarded as statistically significant. Statistical analyses were performed using R (version 3.5.3).Quantitative variables of normal distribution were represented using mean ± standard deviation (SD). If not, medians (interquartile range (IQR)) are used. Qualitative variables were described as frequency and percentage; for comparative analysis among the three groups, analysis of variance (ANOVA) was employed for quantitative variables with normal distribution, and the Kruskal–Wallis test was used for the nonnormal distribution. Pearson’s chi-square test or Fisher’s exact test was employed for qualitative variables. Observed frequencies of different genotypes were separately tested for deviation from the Hardy–Weinberg equilibrium using the exact test. All significance tests were two-sided, and a n = 51), heterozygosity in 41.88% (n = 80), and homozygosity for the T allele in 31.42% (n = 60) of patients. According to published studies, our infertile male patients had a greater frequency of the MTHFR 677T allele than the general population, and the allele frequency for C677T was in Hardy–Weinberg equilibrium , clinical conditions (BMI (p = 0.12), duration of infertility (p = 0.22), type of infertility (p = 0.96), and maternal baseline FSH concentration (p = 0.10) were not statistically different between the three groups , heterozygote mutated (heterozygosity), and mutated homozygote . Age  Table 3.p = 0.37), high-quality embryo rate ), blastocyst formation rate , implantation rate , and clinical pregnancy rate . We further examined whether any of the genotypes could influence the pregnancy outcomes, and the results showed that there were also no significant differences in terms of miscarriage rate ) or live birth rate ) among the three groups , birth height (p = 0.75), birth weight (p = 0.35), neonatal sex (p = 0.48), gestational age at delivery (p = 0.24), and Apgar score (p = 0.34). In addition, no statistically significant differences in terms of birth defects  were observed among the three MTHFR C677T genotype groups. The birth defect of one case in the CT group is congenital heart disease, and the birth defect of three cases in the TT group is of patent foramen ovale of heart, congenital heart disease, and cerebral hemangioma.The neonatal outcome was evaluated based on gestational age at delivery, preterm delivery, birth height, birth weight, neonatal sex, and Apgar score among the three groups Table 5.N = 191) in our research seems insufficient. This is one of the limitations of our study. It should be emphasized that although there was no statistically significant difference, the proportion of birth abnormalities was higher in the MTHFR 677TT group. Possibly, increasing the sample size could bring about more convincing results.The MTHFR enzyme is a key enzyme in folate metabolism and is necessary for the homocysteine conversion to methionine . The 677There has recently been evidence that the MTHFR polymorphism 677 C>T) is associated with male infertility in different populations , 14, 26.7 C>T is In conclusion, we did not find any association between the paternal MTHFR C677T polymorphisms and embryonic quality, pregnancy outcomes, including miscarriage, live birth rate, or neonatal outcomes, such as preterm delivery, birth height, birth weight, or gestational age at delivery. Further studies investigating the combined effect of paternal MTHFR polymorphisms on ICSI outcomes with larger sample sizes are recommended.The original contributions presented in the study are included in the article/supplementary material. Further inquiries can be directed to the corresponding authors.The studies involving human participants were reviewed and approved by the Ethical Committee of the First Affiliated Hospital of USTC . The patients/participants provided their written informed consent to participate in this study.JH and YW designed the studies. YW and BX collected the data. XJ, YW, and WL performed the data analysis. JH and XJ wrote the manuscript. BX revised the manuscript. All authors reviewed and approved the final manuscript.


Objective: To examine factors associated with birth-related post-traumatic stress disorder (PTSD) among women who had preterm birth in their last pregnancy in Turkey.Methods: 304 women were asked to report sociodemographic factors, perinatal factors, birth-related factors, preterm birth/premature infant characteristics, and social support factors and PTSD symptoms. Data were collected using online surveys between November 2020 and February 2021. Hierarchical multiple linear regression was used. Results: The prevalence of birth-related PTSD symptoms following preterm birth was 71.1%. Older age, the woman being positively affected by her own mother’s birth experience, not having traumatic experience in pregnancy and in the postnatal period, lower stress level after traumatic events experienced during birth, not feeling that their life/physical integrity was at risk during birth, having amniotomy, feeling psychologically well after childbirth, not being negatively affected by witnessing other parents’ happy moments with their babies in friend/family groups, the absence of infant illness and mother’s reporting higher positive interactions with healthcare team were associated with decreased likelihood of birth-related PTSD. Except for age and traumatic event in the postnatal period, all the variables explained 43% of the variance with a small effect size (f2 = 0.04). Stress level after the traumatic events experienced during labor was the strongest predictor of birth-related PTSD symptoms (β = 0.33). Conclusion: Wellbeing of mother and baby, facilitating interventions at labor, and positive communication with the healthcare team was associated with lower birth-related PTSD symptoms. The study findings highlighted on birth-related PTSD symptoms in mothers of preterm infants in Turkey. Women were asked to complete the survey using an online survey platform (forms.google.com). The link to the survey was shared through Facebook groups, WhatsApp groups, and Instagram stories by researchers (GGI and FI) and students doing an internship in the Midwifery Department at Mersin University in Turkey to reach participants who met the inclusion criteria. Data collection began on 17 November 2020 and ended on 22 February 2021. This study was approved by the Ethical Committee of the Niğde Ömer Halisdemir University . All the participants were given information about the study and online informed consent was obtained.“How were you affected by your own mother’s birth experience?”). The measures used in the study are detailed as follows:This form was created by the authors and comprised questions relating to sociodemographic details, PTSD symptoms, prenatal and perinatal characteristics, birth-related factors, preterm birth/premature infant characteristics, and social support characteristics of the participants . Additionally, a single item was used to capture intergenerational impacts of birth by asking participants to evaluate their perceptions of their mothers’ birth experience as positive or negative , who did not specify the date of birth of their baby (n = 4), and who lost her baby after birth (n = 1) were not included in the analysis. The final sample size consisted of 304 women.Overall, 324 women completed the survey. Women who reported their symptoms were due to medication, substance use, or other illness, . Most women were married , highly educated , and living in a city , and all reported having middle income . Participants’ characteristics are reported in Table Participants ranged in age from 20 to 51 years (% (n = 216) of women had at least one of the birth-related PTSD symptoms in the first six and more than six months after birth. One hundred and eightyfive women (60.9%) experienced symptoms from at least one of the birth-related PTSD symptom categories in the first six months after birth, and 31 (10.2%) had symptoms that continued for more than six months.In total, 71.1Correlations between PTSD and study variables are reported in Table The results of the hierarchical multiple linear regression are reported in Table % of variation in PTSD symptoms. As for the intergenerational transmission variable, we found that women who were affected positively by her own mother’s birth experience were associated with decreased birth-related PTSD symptoms, explaining 0.5% of variation in birth-related PTSD symptoms. With respect to prenatal and perinatal characteristics, not having traumatic experience in pregnancy and in the postnatal period was associated with decreased birth-related PTSD symptoms. These variables explained 11%, and 12% variation in birth-related PTSD, respectively. With respect to birth-related factors, lower stress level after traumatic events experienced during birth, not feeling that their life/physical integrity was at risk, having an amniotomy, and feeling psychologically well after birth were associated with decreased birth-related PTSD, explaining 32%, 34%, 37% and 38% variation in birth-related PTSD symptoms, respectively. In addition, with respect to preterm birth and having premature infant characteristics, not being negatively affected by witnessing other parents’ happy moments with their babies in friend/family groups and the absence of the illness in the infant were associated with decreased birth-related PTSD symptoms, explaining 40% and 41% of the variance in birth-related PTSD, respectively. Finally, with respect to social support characteristics, mothers who reported more positive interactions with the healthcare team were associated with decreased birth-related PTSD symptoms. All variables together explained 43% of the variance of birth-related PTSD symptoms with a small effect size (f2 = 0.04). It was observed that all variables contributed to the variance alone, except for age and traumatic events in the postnatal period. Considering beta values, the strongest predictor (β = 0.33) of birth-related PTSD symptoms was the stress level after traumatic events experienced during birth.With respect to sociodemographic characteristics, older age was associated with decreased overall PTSD symptoms scores and explained 0.2% of women with preterm birth experience had at least one PTSD symptom, 60.9% experienced PTSD symptoms in the first 6 months, and 10.2% experienced PTSD symptoms more than 6 months. This finding has links with the study by Barthel et al.  might have captured mothers who were more digitally proficient. In addition, self-recruitment via the web might lead to an unrepresentative sample. Third, participants’ age range (20–51 years) was very large and childbirth care and medical practices, such as the advent of family centered care, have changed in recent years in Turkey. Fourth, the socioeconomic status of the participants  was very narrow, and means that the sample is unlikely to be representative. Thus, analyzing the role of age and socioeconomic status in greater detail in larger samples would be necessary in future studies. Additionally, although the time elapsed after birth did not have a significant effect on birth-related PTSD symptoms, it would be useful to consider this in more depth by including more participants at different time intervals. Further mixed-methods studies using quantitative and qualitative evidence may help shed light on key moderating and mediating variables that predict and mitigate against PTSD onset. Fifth, having a wide range of numbers in perinatal factors  could be evaluated as another limitation of the study due to the possibility of undermining equal variances assumptions. Furthermore, excluding criteria that not have any diagnosed mental illness may not likely account for existing mental illnesses that are not reported. This may lead to non-differential misclassification which may deem the results conservative. Sixth, women who experience punitive social consequences associated with a lack of social support or abusive relationships may be at greater risk for perinatal PTSD. Therefore, it would be beneficial to include variables such as domestic violence and emotional abuse in future studies. Finally, in this study, the total symptom scores of PTSD were used. However, evaluating which clusters of PTSD symptoms are most strongly associated with which factors would be a suggestion for future studies.Despite the limitations, this study has highlighted key factors that may protect against mothers developing PTSD symptoms following a premature infant; namely older age, the woman having positive perceptions of her own mother’s birth experience, not having traumatic experience in pregnancy and in the postnatal period, lower stress level after traumatic events experienced during birth, not feeling of life/physical integrity at risk, amniotomy, feeling psychologically well after birth, having tolerance seeing their happy moments with their babies in friend/family groups, the absence of the illness in the infant and mother’s higher interaction with healthcare team were associated with decreased birth-related PTSD symptoms.The findings from this study have important implications for public health and clinical interventions. This study has shown once again that the routine screening of birth-related PTSD is crucial for maternal and infant health. It has great importance for women to have good conditions both during pregnancy and in the postpartum period. Giving place the constructs which contribute to diminishing stress level in interventions is one of the significant implications of the current study. Considering the feeling that their life/physical integrity was at risk during birth and the role of stress level after the traumatic events during labor on birth-related PTSD symptoms, a respectful, humanized, consented and positive maternity care should be given to women. Based on the association between higher positive interactions with healthcare team and decreased likelihood of birth-related PTSD, we may conclude that training for neonatal nurses, midwives, obstetricians, gynecologists, psychologists, psychiatrists, and the wider team working in postpartum health is an inevitable implication. Lastly, approaches that contribute to improving psychological well-being in perinatal processes may be protective for birth-related PTSD symptoms following preterm birth, but this needs to be examined further.Evaluation of birth-related PTSD symptoms in the postpartum period is crucial for perinatal mental health. For this reason, in the postpartum period, professionals  should evaluate women’s symptoms regarding birth-related PTSD with the valid and reliable measurement tools and clinical evaluation, guide them in realizing usual and unusual emotions, cognitions and behaviors following birth, guide them in the process of dealing with problematic issues if any, and offer counseling to women about birth-related PTSD.Finally, multidisciplinary, multicentric and cross-national studies on this topic are needed, using robust methods and representative samples.


To determine if blastocyst trophectoderm biopsy for PGT-A is associated with an increased rate of live birth per embryo in good prognosis IVF patients at a single center.We performed a retrospective cohort study of good prognosis embryo transfer cycles at a single center from 1/1/2017 to 12/31/2019. We evaluated the rate of live birth per embryo with and without PGT-A for transfer of embryos in two groups of good prognosis patients: embryos from donor oocytes and embryos from autologous oocytes with maternal age less than 35 years at oocyte retrieval. Two-sided Fisher’s exact tests were used for comparisons between groups.p < 0.01). After transfer of embryos created from autologous oocytes with maternal age less than 35 years at oocyte retrieval the live birth rate per euploid embryo was 70.0% (49/70) compared to 52.5% (53/101) for untested embryos for a rate difference of 17.5% .After transfer of embryos created from donor oocytes the live birth rate per euploid embryo was 70.6% (24/34) compared to 34.3% (35/102) for untested embryos for a rate difference of 36.3% (95% CI 18.4–54.1%, In good prognosis patients at our center the live birth rate per euploid blastocyst was higher than for untested blastocysts. Theoretically PGT-A has the potential to benefit patients of all ages. Although the main benefit is to increase the live birth rate per embryo transferred, additional benefits include decreased rate of spontaneous abortion and genetically abnormal pregnancy –3. At ouSeveral studies have shown no benefit. A large retrospective paired cohort study of donor oocyte–recipient cycles found no difference in live birth comparing paired outcomes after PGT-A versus no PGT-A when evaluating outcomes of the first or all embryo transfers from 6 frozen donor oocytes . A 2017 On the other hand, some studies have shown increased ongoing pregnancy rates after PGT-A compared to morphological selection only. A 2012 prospective randomized study by Yang et al. in patients under 35 years found an ongoing pregnancy rate after fresh blastocyst single embryo transfer of 69% using selection with PGT-A by aCGH compared to 42% with selection by morphology alone .There are two main reasons we would not want to use PGT-A: misclassification of viable embryos as aneuploid and damage to the embryo from the biopsy . A recenThe objective of this study was to determine if the live birth rate per embryo at our center is higher for embryos selected by PGT-A than for untested embryos in good prognosis patients.This retrospective cohort study included 232 embryo transfers of 307 embryos from 2017 through 2019 at a single center  to separate the biopsy cells from the embryo. 90% of embryo biopsies were performed by the laboratory director and 10% were performed by a senior embryologist. PGT-A was performed using next generation sequencing . 95% of frozen embryo transfers at our center were performed in programmed cycles using 50 mg of IM progesterone in ethyl oleate daily and 200 mg of micronized progesterone vaginally twice a day. Blastocyst transfer was performed on day 6 of progesterone, approximately 108 h after the start of progesterone exposure.Fisher’s exact test was used to compare rates of live birth per embryo . This study had 80% power to detect a 17% absolute difference in live birth rate per embryo between the PGT-A and non PGT-A groups for all data combined at a two-sided alpha level of 0.05. For embryos from donor oocytes there was 80% power to detect a 28% difference at this same significance level. For embryos from autologous oocytes there was 80% power to detect a 22% difference at this same significance level. There were no clinically significant differences in baseline demographics or clinical characteristics that were expected to have a large impact on live birth rates (Table p < 0.01). For untested embryos created from donor oocytes the live birth rate was 30.4% (7/23) when vitrified oocytes were used and 35.4% (28/79) when fresh oocytes were used.After transfer of embryos created from donor oocytes the live birth rate per euploid embryo was 70.6% (24/34) compared to 34.3% (35/102) for untested embryos for a rate difference of 36.3% .After transfer of embryos created from autologous oocytes with maternal age less than 35 years at oocyte retrieval the live birth rate per euploid embryo was 70.0% (49/70) compared to 52.5% (53/101) for untested embryos for a rate difference of 17.5% , as shown in Fig. Overall analysis with data from both groups combined showed the live birth rate per euploid embryo was 70.2% (73/104) compared to 43.3% (88/203) for untested embryos for a rate difference of 26.8%  that occurs with PGT-A testing and culture of embryos to expansion stage 2 before embryo biopsy (Table In this analysis we included use of embryos from fresh and frozen oocytes, fresh and frozen embryo transfer, transfers to gestational carriers, and single and double embryo transfers. Inclusion of these diverse types of transfers makes the data broadly applicable. However, this analysis is less controlled than ideal. Decisions about proceeding with PGT-A and the number of embryos to transfer are made by the patient and physician after considering all aspects of the patient’s medical history including age, expected number of embryos, number of prior spontaneous abortions, and obstetrical history. Limiting the analysis to single frozen embryo transfers of embryos created from fresh oocytes would add more control but based on our data set the numbers would have been too small to have sufficient statistical power. In the analysis in Fig. PGT-A of embryos from good prognosis patients likely increases the live birth rate per embryo transferred if loss of embryo implantations from the biopsy is low. These results support the use of PGT-A in good prognosis patients at centers with data to support proficiency in this technique.


Since 1996, many studies have reported that periodontal disease during pregnancy may be a risk factor for preterm birth and low birth weight; however, in Africa, periodontal disease is considered a non-high-priority disease. In addition, there are few dental facilities in rural Rwanda; thus, the oral condition of pregnant women has not been investigated. The objective of this study was to assess the tooth brushing habits of pregnant women in rural Rwanda and evaluate whether periodontal bacteria in the oral cavity of pregnant women are related to birth outcomes or oral cleaning habits.A questionnaire survey and saliva collection were conducted for pregnant women in the catchment area population of Mibilizi Hospital located in the western part of Rwanda. Real-time PCR was performed to quantitatively detect total bacteria and 4 species of periodontal bacteria. The relationship of the copy number of each bacterium and birth outcomes or oral cleaning habits was statistically analyzed.Tannerella forsythia, and Treponema denticola were correlated with lower birth weight . The sex ratio at birth was higher in women who had high copy numbers of Porphyromonas gingivalis and T. denticola during pregnancy . Furthermore, regarding the correlation between oral cleaning habits and the amount of bacteria, the more frequently teeth were brushed, the lower the level of P. gingivalis (p = 0.0061); the more frequently the brush was replaced, the lower the levels of P. gingivalis and T. forsythia .Among the participants, high copy numbers of total bacteria, This study suggested that improving tooth brushing habits may reduce the risk of periodontal disease among pregnant women in rural Rwanda. It also indicated that the amount of bacteria is associated with various birth outcomes according to the bacterial species. Both access to dental clinics and the oral cleaning habits of pregnant women should be important considerations in efforts to alleviate reproductive-related outcomes in rural Africa.The online version contains supplementary material available at 10.1186/s12903-022-02443-4. Periodontal disease is known to cause many complications. For instance, pregnant women with periodontal disease are at increased risk of preterm birth and delivering low-birth-weight infants. However, the importance of oral care during pregnancy is not an important consideration in rural Africa, where preterm birth rates and low-birth-weight rates are particularly high. Moreover, even the oral hygiene status of pregnant women has not been assessed in such areas. In this study, we focused on the amount of periodontal bacteria that cause periodontal disease and investigated the relationship between the amount of bacteria and birth outcomes. Our findings indicate that tooth brushing guidance for pregnant women and improved access to dental clinics in rural Africa may contribute to reduced rates of preterm birth and low birth weight.The online version contains supplementary material available at 10.1186/s12903-022-02443-4. For many years, periodontal disease was treated only in the dental field; however, in 1996, Offenbacher et al. reported for the first time that periodontal disease during pregnancy may induce preterm birth and low birth weight . In factA survey was conducted with pregnant women who were outpatients or hospitalized at Mibilizi Hospital in the Rusizi district, western Rwanda Fig. . PregnanPorphyromonas gingivalis, Tannerella forsythia and Treponema denticola) and Prevotella intermedia. Specific primers  against each 16S rRNA region and probes labeled with FAM at the 5' end and TAMURA at the 3' end  were used. We also performed real-time PCR using universal primers targeting the common bacterial 16S rRNA sequence to evaluate the copy number of total bacteria in the saliva , and the DNA of periodontal bacteria was quantitatively detected by real-time PCR using a LightCycler 480 . We targeted 4 species, including 3 “red complex” species  and R studio were used for the statistical analyses.The data from the questionnaire survey were summarized descriptively, and Spearman's rank correlation coefficient, Fisher's exact test, Welch’s t test, Wilcoxon's rank sum test, the Cochrane Armitage test, linear regression analysis, and a generalized linear model were used for statistical analysis. A In all, 153 women who had a single fetus were included in this study. The average age of the pregnant women was 31.2 ± 6.5 years, and the average gestational age at participation was 27.7 ± 3.8 weeks  for T. denticola, and 93.5% (n = 143) for P. intermedia and was the lowest at 58.8% (n = 90) for P. gingivalis. Only 1.3% (n = 2) of the pregnant women did not have any of the 4 species of periodontal bacteria  for T. forsythia, 1.00E5 (1.88E4 –2.32E5) for T. denticola and 3.13E3 (6.47E2 –1.05E4) for P. intermedia in positive subjects .The positive rate of periodontal bacteria among the pregnant women was 97.4% (n = 149) for 1.3% n =  of the p1.3% n =  of the pSince twin fetuses generally tend to be born smaller than single fetuses, the data from 153 fetuses, excluding the twin fetuses from 3 pregnant women, were used for statistical analysis. Table p = 0.0032, p = 0.0286). In the analysis using the copy number of P. gingivalis as the objective variable, the sex ratio at birth  was significantly higher in pregnant women with a high copy number .The relationship between the copy number of each bacterium and birth outcomes was analyzed in univariate . On the other hand, birth weight showed a negative correlation with the copy number of T. forsythia (p = 0.0212).In the multivariate analysis, maternal age and birth length showed a positive correlation with the copy number of T. denticola, the univariate analysis showed a positive correlation with birth length and sex ratio at birth . In the multivariate analysis, birth weight was negatively correlated with bacterial mass (p = 0.0288), and birth length was positively correlated (p = 0.0033). In addition, a large amount of bacterial mass showed a significant positive correlation with the sex ratio at birth (p = 0.0043).In the analysis regarding the bacterial mass of P. intermedia was not significantly correlated with any of the birth outcomes in either the univariate or multivariate analysis.The bacterial mass of In terms of the frequency of daily tooth brushing among the participants, 75.7% (n = 115) brushed only once a day Table . In addiP. gingivalis was significantly lower in the group of pregnant women who brushed their teeth more than once a day than in the group of pregnant women who brushed only once per day (p = 0.0061) . In addition, the pregnant women with a history of dental examination had significantly lower levels of all four species than those without a history of dental examination . However, the tools for tooth brushing were not related to the copy number of any of the bacterial species.An analysis of the relationship between the frequency of tooth brushing and the copy number of each bacterium was conducted. The copy number of 1) Table . In addiA previous epidemiological survey targeting 7525 pregnant women in 30 districts in Rwanda found that 17.0% of pregnant women were over 35 years old , and in In Africa, the total fertility rate of women aged 15–49 years is known to be higher in rural areas than in urban areas . The totT. forsythia, which is the causative agent of severe periodontal disease, tended to increase as the age of the pregnant women increased, which is consistent with previous reports. Although the other bacterial species detected in this study did not correlate with the age of the pregnant women, our findings suggest that the bacterial species, whose mass is affected by the aging of the host, may differ depending on the lifestyle, eating habits or tooth brushing habits of the women.The prevalence of periodontitis increases with age . In thisT. forsythia and T. denticola were correlated with birth weight in this study. Previous studies have also reported that a large copy number of T. denticola in the oral cavity increases the risk of preterm low birth weight in China [T. denticola generally influences fetal development regardless of the country.It has been reported that periodontal disease among pregnant women promotes an inflammatory reaction and increases the risk of low birth weight . In thisin China , so it iT. denticola and gestational age even though p value was not under 0.05. It’s possible that the high copy number of T. denticola affect to the reduction in both gestational age and birth weight in this area.Our findings also suggested that there may be weak correlation between the copy number of T. denticola from the placenta was higher in pregnant women with threatened preterm birth than in normal pregnant women [T. denticola in the oral cavity may be a risk factor for preterm birth.Previous studies have suggested that infections in pregnant women, especially oral, intrauterine, amniotic fluid, urinary tract, vaginal infections, and pneumonia, are associated with preterm birth , 22. In nt women . AlthougP. gingivalis and T. denticola. Previous studies have reported that the sex of the fetus may affect the maternal immune response. For example, when the serum of women who were pregnant with a female fetus was stimulated by lipopolysaccharide, they produced higher interleukin-6 (IL-6) and interleukin-1β (IL-1β) levels than women who were pregnant with a male fetus [The sex ratio at birth was significantly higher in the pregnant women with high copy numbers of le fetus . There ile fetus . Thus, iTransglutaminase 2 (TG2), a protein cross-linking enzyme, is thought to be associated with the activation of NF-κB, which is a regulator of inflammation. In fact, human periodontal ligament cells (HPDL cells) collected from patients with chronic periodontitis had higher levels of inflammatory cytokines, including IL-6, TNF-α, and HMGB-1, than HDPL cells collected from healthy individuals. In addition, the TG2 mRNA levels were also higher. In other words, TG2 may be involved in the early stages of the inflammatory response that occurs in periodontal disease. Therefore, measuring TG2 levels in the blood is also useful for monitoring inflammation during pregnancy, and in the future, simultaneous observation of the carrying status of periodontal bacteria and blood TG2 levels during pregnancy may clarify the relationship of TG2 with all pregnancy outcomes . It has Tooth brushing at least twice a day is recommended to maintain oral hygiene . A surveThe frequency of toothbrush replacement also affects oral hygiene. Worn toothbrushes lose their ability to remove plaque; thus, it is recommended that toothbrushes be replaced when the bristles are worn or every 3 to 4 months of use at least . More thIn addition to oral cleaning habits, restricted access to dental clinics is also a cause of deterioration of the oral environment. In a study conducted in Nigeria, only 12.5% of pregnant women had a history of access to a dental clinic , similarTooth brushing habits generally tend to deteriorate in the elderly generation , 38. In P. gingivalis was significantly higher in the pregnant women who brushed their teeth less frequently. Less frequent brushing has been reported to increase the prevalence of severe periodontal disease [P. gingivalis and T. forsythia were high in the pregnant women who infrequently changed their toothbrushes, it is necessary to provide health guidance and material support so that toothbrushes are changed every 3 months of use.Among the participants in this study, the copy number of  disease  and incr disease . These rP. gingivalis, alveolar bone resorption was not enhanced in the knockout mice, suggesting that NLRP3 is strongly involved in P. gingivalis-induced bone metabolism and bone resorption, that is, alveolar bone dissolution [Insufficient tooth brushing habits increase periodontal bacteria and promote oral inflammation. The nucleotide-binding oligomerization domain-like receptor family pyrin domain-containing 3 (NLRP3) is one of the constituents of the inflammasome, a protein complex involved in inflammatory response mechanisms. When NLRP3 knockout mice and wild-type mice were exposed to solution . Metformsolution . In addisolution . Howeversolution . Varioussolution . In dentsolution . In addisolution . This stOur findings also indicate that it is important to visit a dental clinic to prevent periodontal disease and preterm low birth weight because the copy numbers of all four bacterial species tended to be low in the group of pregnant women who had visited a dental clinic. As shown in Additional file In this study, for the first time, we simultaneously analyzed the relationship between the amount of periodontal bacteria in the oral cavity, tooth brushing habits, and pregnancy outcomes in pregnant women in Africa. Other preterm birth risk factors were also investigated. It was previously revealed that the risk of preterm low birth weight was increased in those with low lipid and vitamin E intake during pregnancy , malariaThis study showed that carrying a high copy number of periodontal bacteria during pregnancy may be associated with a risk of low birth weight in rural Rwanda. In addition, inadequate oral cleaning habits are associated with an increase in the copy number of bacteria in the oral cavity, and the oral condition during pregnancy may affect not only birth weight, which have been the focus of previous studies, but also other birth outcomes, including the sex of the fetus. Therefore, especially in rural Africa, where medical resources are limited, tooth brushing guidance, which includes the recommendation for using chlorhexidine mouthwash and improved access to dental clinics, is important to prevent periodontal disease among pregnant women and women who may become pregnant and to reduce the burden of premature birth and low birth weight.Additional file 1. Sequence data of primers and probes used to detect periodontal bacteria, results of univariate analysis not shown in the text, relationship between age group of pregnant women and toothbrushing habits, and figure indicating the number of dentists per population by countries.Additional file 2. Raw data of the number of bacteria calculated from the amount of DNA detected by real-time PCR.


Coffee consumption has been associated with several adverse pregnancy outcomes, although data from randomized–controlled trials are lacking. We investigate whether there is a causal relationship between coffee consumption and miscarriage, stillbirth, birthweight, gestational age and pre-term birth using Mendelian randomization (MR).N = 91 462) from the Coffee and Caffeine Genetics Consortium. Outcomes included self-reported miscarriage ; the number of stillbirths [N = 60 453 from UK Biobank (UKBB)]; gestational age and pre-term birth  and birthweight (N = 297 356 reporting own birthweight and N = 210 248 reporting offspring’s birthweight from UKBB and the Early Growth Genetics Consortium). Additionally, a one-sample genetic risk score (GRS) analysis of coffee consumption in UKBB women (N up to 194 196) and the Avon Longitudinal Study of Parents and Children (N up to 6845 mothers and 4510 children) and its relationship with offspring outcomes was performed.A two-sample MR study was performed using summary results data from a genome-wide association meta-analysis of coffee consumption (Both the two-sample MR and one-sample GRS analyses showed no change in risk of sporadic miscarriages, stillbirths, pre-term birth or effect on gestational age connected to coffee consumption. Although both analyses showed an association between increased coffee consumption and higher birthweight, the magnitude of the effect was inconsistent.Our results suggest that coffee consumption during pregnancy might not itself contribute to adverse outcomes such as stillbirth, sporadic miscarriages and pre-term birth or lower gestational age or birthweight of the offspring. Key MessagesBoth weighted and unweighted maternal genetic risk scores for higher coffee consumption were associated with elevated coffee consumption at Week 32 of gestation.Maternal coffee consumption during pregnancy may not contribute to adverse outcomes such as stillbirth, sporadic miscarriages and pre-term birth.Maternal coffee consumption during pregnancy may influence birthweight of the offspring.,Coffee is the most consumed beverage worldwide, with an average daily intake of >400 mg of caffeine, equivalent to approximately four cups,,It has been estimated that ∼70% of pregnant women in the USA consume caffeine during pregnancy, with coffee being the main source of caffeine.,The current World Health Organization guidelines recommend a caffeine intake of <300 mg/day during pregnancy,,Given it would be infeasible and/or unethical to randomize women to consume different levels of coffee during pregnancy, alternative methods for addressing the possible causal effect of maternal coffee consumption on pregnancy outcomes are needed. Mendelian randomization (MR), which uses genetic variants related to an exposure of interest as instruments for that exposure, is less prone to confounding by social, environmental and behavioural factors that affect many traditional observational epidemiological studies.http://www.nealelab.is/uk-biobank; 10 December 2020, date last accessed) and gestational age and pre-term birth from 23andMe, Inc.IJE online). Detailed descriptions of these analyses are listed below in the sections ‘Two-sample MR analyses’, ‘Individual-level data MR analysis using GRS (ALSPAC and UKBB)’ and ‘Associations between self-reported coffee consumption and pregnancy outcomes in the ALSPAC study’.Genetic instruments were identified in a genome-wide association study (GWAS) of coffee consumptionN = 91 462 individuals of European ancestry).IJE online).Eight single-nucleotide polymorphisms (SNPs) that were significantly associated with coffee consumption were extracted from summary results data from a GWAS of coffee consumption published by the Coffee and Caffeine Genetics Consortium (https://egg-consortium.org/birth-weight-2019.html).Summary results statistics from the GWAS of birthweight were obtained from the Early Growth Genetics (EGG) consortium and UKBB meta-analysis   that involved 60 453 women from UKBB who reported the number of stillbirths they experienced.Summary results statistics from the GWAS of the number of self-reported stillbirths were obtained from publicly available summary statistics published by the Neale lab  were obtained from 23andMe. These results contributed to the discovery data set for a previously published GWAS by Zhang IJE online). First, we selected eight independent SNPs that reached genome-wide significance in the GWAS of coffee consumption mentioned above .,P-value threshold of 5 × 10−8. The GCKR variant (rs1260326) was associated with alcohol intake frequency, type 2 diabetes, fasting glucose levels, triglycerides levels, cardiovascular disease risk factors and chronic kidney disease, and the SNP rs6265 in the BDNF gene had previously been associated with several traits, including body mass index, weight, body fat and smoking (IJE online).We selected three sets of SNPs to instrument coffee intake (N = 173 259), having a stillbirth (N = 78 867) or having a spontaneous miscarriage (N = 78 681). Five out of eight SNPs were associated with either alcohol consumption or smoking behaviour, after Bonferroni correction (P < 0.05/8 = 0.00625) (IJE online). Therefore, for the third subset of SNPs, we kept three out of the eight SNPs , which were not associated with smoking or alcohol intake in UKBB and had no strong evidence for pleiotropy in the above search in PhenoScanner,IJE online). This analysis was performed because the GRS for coffee consumption had been found to be associated with smoking behaviour and alcohol intake frequency in UKBB previouslyFurther, we tested the association between each of the eight SNPs and alcohol consumption and smoking behaviour in 194 196 UKBB women who reported either offspring birthweight (IJE online). A heterogeneity test of causal effect estimates was conducted across each of the variants for coffee consumption using Cochran’s Q. Directional pleiotropy was tested by assessing whether the MR–Egger intercept was different from zero. Sensitivity analyses were performed using MR–Egger regression, weighted median, weighted and simple mode estimation approaches. I2GX was calculated to assess the potential for weak instrument bias in the MR–Egger regression analyses. However, due to the small number of variants used in the MR analyses, the ability of these methods to control for latent horizontal pleiotropy is likely to be limited. Bonferroni correction of P-value for the two-sample MR analysis was 0.05/5 phenotypes tested = 0.01.A two-sample inverse-variance weighted (IVW) MR analysis was conducted using either eight, six or three genetic variants as explained above to estimate the causal relationship of maternal coffee consumption on sporadic miscarriages, stillbirths, gestational age, pre-term birth and offspring birthweight. All SNPs and their effect sizes for these phenotypes are listed in IJE online). The TwoSampleMR packageA flowchart showing the number of individuals included in each analysis is presented in IJE online).UKBB is a large prospective population-based cohort containing ∼500 000 individuals , representing 5.5% of those who were invited to participate.N = 20 937), stillbirth (N = 115 329) or spontaneous miscarriage (N = 115 329), leaving a total of 194 196 women who reported any of the birth outcomes along with their coffee consumption habit. The exact number of women who reported the number of stillbirths and miscarriages was 78 867 and 78 681, respectively. Out of the 194 196 women, only a total of 155 242 reported both their offspring birthweight and maternal age at birth. A detailed description of the phenotypes is presented in IJE online).We removed UKBB women of European ancestry who did not report any information on their offspring's birthweight .ALSPAC is a longitudinal birth cohort study established to understand how genetic and environmental factors influence health and development in parents and children.Birthweight data for each child in the study were ascertained in a variety of ways, including from obstetric data records, recorded by the ALSPAC research team and from the birth notification service in the UK. If the birthweight measurement for an individual differed across the different sources (defined as >100 grams difference), the individual was excluded from the analysis. When the differences were ≤100 grams, the lower birthweight measurement was used. In the study, we excluded offspring with birthweight of <2.5 or >4.5 kg to match the inclusion criterion of the GWAS of birthweight. Gestational age was defined as the weeks of gestation based on the final clinically estimated date of delivery and pre-term birth was defined as <37 weeks of gestation.N = 6845). Maternal alcohol drinking was derived from units of alcohol drunk per week at Week 32 of pregnancy, with those who did not drink defined as non-drinkers (N = 2826) and the rest defined as drinkers (N = 1525). Maternal smoking was derived from the smoking behaviour in the first trimester of pregnancy, with those smoking any types of tobacco defined as smokers (N = 1620) and the rest defined as non-smokers (N = 5702). These data were all collected from a self-reported questionnaire.Maternal coffee intake was defined as cups of coffee per day at Week 32 of pregnancy , 1.81% (six SNPs) and 0.82% (three SNPs) of the variance in coffee drinking according to the effect estimates reported in the exposure GWAS.Linear regression analyses were used to assess the relationship between the maternal GRSs for coffee consumption (both weighted and unweighted) and self-reported and maternal coffee intake (cups/day) in addition to the number of spontaneous miscarriages, number of stillbirths and birthweight of the first offspring, adjusting for maternal age at birth (to reflect age at the pregnancy in question). Maternal age was only available for birthweight as women only reported their total number of miscarriages or stillbirths. To match the inclusion criterion of the GWAS of birthweight, if the birthweight of the offspring was <5 or >10 pounds , the value was excluded from the analysis. Gestational age and pre-term birth were only available in a small subsample in UKBB, and therefore were not included in the analyses here.IJE online).Additionally, we utilized the mother–offspring pairs in UKBB and performed a linear regression of maternal unweighted GRS for coffee consumption and offspring own-reported birthweight, adjusting for offspring unweighted GRS. We also conducted linear regression of maternal weighted GRS for coffee consumption on offspring own-reported birthweight, adjusting for individual offspring SNPs.P = 0.002; IJE online). Therefore, when we identified an association between the GRSs of coffee intake that incorporated rs2472297 (i.e. the two sets of GRSs constructed using eight and six SNPs) and pregnancy outcomes, we conducted sensitivity analysis by including smoking as a covariate in the analysis.One of the strongest instruments for coffee intake, rs2472297, is also associated with smoking in the female population in UKBB (IJE online).A flowchart showing the number of individuals included in each analysis is presented in N = 4510 for birthweight and 2989 for gestational age and pre-term birth) and without  conditioning on child’s unweighted GRS or individual SNPs as described above in UKBB analysis. Covariates included maternal age at the last menstrual period and child’s sex. Analyses were conducted using a linear regression model for birthweight and gestational age, and a logistic regression model for pre-term birth.We constructed three weighted and three unweighted GRSs of coffee consumption as described above. We examined the association between the GRSs and maternal coffee intake (cups/day) at Week 32 during pregnancy in 6845 mothers. We also examined the association between the GRSs of coffee consumption and three pregnancy outcomes, with  using chi-square tests.IJE online).A flowchart showing the number of individuals included in each analysis is presented in To explore whether previous observational associations regarding coffee consumption and birthweight were applicable to ALSPAC, we examined the phenotypic association between maternal coffee intake at Week 32 during pregnancy and the three pregnancy outcomes, including (i) child’s birthweight in 4302 mother–child pairs, (ii) weeks of gestation at birth, pre-determined by ALSPAC using estimated due date and (iii) pre-term birth defined as <37 weeks of gestation in 4231 mother–child pairs. We did not include analysis of stillbirth and miscarriage as we did not have information regarding coffee consumption in the pregnancy that ended in these outcomes.Analyses were conducted using a linear regression model for birthweight and gestational age, and a logistic regression model for pre-term birth. Covariates included maternal age at the last menstrual period, maternal smoking and alcohol intake during pregnancy, and child’s sex.IJE online). All statistical analyses were performed in R (version 3.4.3).A flowchart showing the number of individuals included in each analysis is presented in https://zzz.bwh.harvard.edu/gpc/qtlassoc.html).https://shiny.cnsgenomics.com/mRnd/).We were interested in the statistical power of our study to detect the causal effect of maternal coffee consumption on different pregnancy outcomes. For the unconditional GRS analyses, we used the ‘Genetic Power Calculator’ (IJE online). The effects estimated using eight or three SNPs were in the same direction, but the effect sizes were attenuated. The 95% CIs around the estimated causal effect on the number of reported stillbirths, risk of sporadic miscarriages, pre-term births and gestational age overlapped zero. SNPs included in the GRSs are listed in IJE online).We observed an effect of increased maternal coffee consumption on increased offspring birthweight in the analysis including six SNPs  (IJE online); however, due to the small number of variants, these sensitivity analyses are included only for completeness. The IVW heterogeneity analysis showed no strong evidence of heterogeneity in the causal effect estimate for coffee consumption on number of stillbirths, spontaneous miscarriage, gestational age, pre-term birth or birthweight, except for the birthweight analysis with all eight SNPs included in the model . Likewise, we found no evidence of directional pleiotropy for maternal coffee consumption on any of the outcomes (IJE online). However, due to the small number of variants in the analysis, the MR–Egger results should be carefully interpreted. The I2GX of >0.99 was observed for all analyses, well above the cut-off of 0.9, which suggests little influence of weak instrument bias in the MR–Egger analysis.Sensitivity analyses using MR–Egger, Weighted Median, Simple and Weighted Mode showed similar trends to the IVW estimates (IJE online). The GRSs for coffee consumption were tested for association with the number of cups of coffee consumed per day in all female individuals from UKBB. An association was found between coffee consumption (N = 194 196) and the different unweighted and weighted GRSs (IJE online), suggesting that having more coffee consumption increasing alleles identified in the sample of both men and women would increase a woman’s coffee consumption.An overview of the demographics of the women included in the different analyses can be found in N = 78 681) and stillbirths (N = 78 867) showed no association (N = 155 242)   and the N = 2965). We were not able to detect any associations between maternal GRS and offspring birthweight in these analyses . Both weighted and unweighted GRSs of maternal coffee consumption constructed using either eight or six SNPs were associated with increased coffee consumption at Week 32 of gestation  in ALSPAC. Although the GRSs constructed using three SNPs were not associated with coffee consumption during pregnancy (P ≥ 0.457), the direction of the effect was the same but the effect size was attenuated. There was no association between any of the GRSs and maternal alcohol drinking or smoking during pregnancy .An overview of the demographics of the women included in the different analyses can be found in IJE online).Maternal GRSs were not associated with offspring birthweight, gestational age or pre-term birth either with or without adjusting for offspring genetics . We alsoA higher maternal self-reported coffee consumption at Week 32 of gestation was associated with a lower offspring birthweight ; however, when adjusting for smoking and alcohol consumption during pregnancy, this association attenuated and the 95% CI overlapped zero . Maternal self-reported coffee consumption was associated with a higher risk of pre-term birth both when adjusting for smoking and alcohol  and without adjustment . We found a similar trend for the association with gestational age with  or without adjusting for alcohol and smoking during pregnancy , even though their 95% CI overlapped zero.IJE online) shows approximate causal effect sizes that we have 80% power to detect in our main analyses. As expected, the power to rule out negative effects depends critically on the amount of variance explained in coffee consumption by our GRSs. In the case of conservative estimates for the amount of variance explained in coffee consumption (i.e. a GRS explaining 0.37% of the variance), we are well powered to rule out moderate to large adverse effects of coffee consumption on many pregnancy-related outcomes . Indeed, if the GRS explains a more substantial proportion of the variance in coffee consumption (i.e. ∼2%), then we are well powered to rule out the action of much smaller negative causal effects (IJE online).et al. using data from UKBB and the FinnGen Consortium, who also found no strong causal relationship between caffeine consumption and pregnancy loss.et al. define ‘pregnancy loss’ as a history of having stillbirth, spontaneous miscarriage or termination (UKBB), or as spontaneous abortion as classified by the International Classification of Diseases 8th to 10th codes (FinnGen). Our results confirm and extend the findings of Yuan etal.We did not find strong evidence for a causal effect of maternal coffee consumption on the number of miscarriages, stillbirths, gestational age or pre-term birth in any of our analyses conducted using either individual-level data from UKBB and ALSPAC or summary level data from 23andMe or publicly available sources. We constructed three sets of genetic instruments associated with coffee consumption in men and non-pregnant women, and found that the instruments containing either eight or six SNPs were associated with self-reported coffee consumption at Week 32 of pregnancy and therefore potentially good instruments for coffee consumption during pregnancy. Our results suggest previously reported observational associationsWe were able to replicate the previously reported observational association between increased maternal coffee consumption during pregnancy and decreased offspring birthweight/higher risk of pre-term birth in ALSPAC, when we did not include smoking and alcohol as covariates. However, the observational association with birthweight attenuated when these variables were adjusted for, suggesting these factors may have confounded previous observational relationships. Additionally, our MR analyses did not support a causal relationship for either outcome.GCKR gene and the BDNF gene known to be associated with type 2 diabetes and body mass index (BMI) and smoking behaviour, respectively. As expected, the SNP in the GCKR gene was associated with birthweight, whereas the SNP in the BDNF gene was associated with both smoking, BMI and birthweight. Both these variants were removed from the analysis when using either six or three SNPs. The inconsistency could also be partly due to the variance in coffee consumption explained by the three SNP GRSs being less than half that explained by the six or eight SNP GRSs. Additionally, these results could not be replicated in the mother–offspring analysis either in UKBB or in ALSPAC, although this could be due to the effect being too small to be detected with the substantially smaller sample size. Overall, the birthweight results should be interpreted with caution, as the results from the eight and six SNP GRSs could reflect pleiotropy from smoking or alcohol-related SNPs.We showed a causal effect of increased maternal coffee consumption on increased offspring birthweight in the analyses using either eight  or six SNPs . The effect sizes were ∼0.05 for the two-sample MR, corresponding to an increase in birthweight of ∼24 grams per cup of coffee drunk each day, whereas the one-sample analysis showed effect sizes corresponding to an increase of ∼16 grams per coffee-drinking-increasing allele. In the analysis with eight SNPs, we included variants in both the One of the strengths of our two-sample MR analysis is the use of partitioned maternal genetic effects from a birthweight GWAS, allowing estimation of the maternal genetic effects on birthweight conditional on the fetal genome and using these effects in the two-sample MR, as well as using conditional mother–offspring analysis for the GRS analysis of birthweight (UKBB and ALSPAC) and analysis of gestational age and pre-term birth (ALSPAC). However, these partitioned genetic effects are naturally not available for stillbirths and miscarriages, and we therefore could not perform MR analysis of the maternal contribution alone.Our approach has a number of limitations, which we discuss in the remaining paragraphs. First, the SNPs used in the analysis were identified in the general population rather than in pregnant women. Nevertheless, we have shown that GRSs consisting of these SNPs are associated with coffee consumption in women during pregnancy, although the effect sizes on coffee consumption appear to be smaller in pregnant women in ALSPAC compared with non-pregnant women in UKBB. This could be a consequence of women drinking fewer cups of coffee during their pregnancy and genetic effect sizes being proportionally reduced.Ideally, our genetic instruments would explain as much variance as possible in coffee consumption in order to have maximum power to estimate any causal effects of maternal coffee drinking on pregnancy-related outcomes. Variance in coffee consumption explained by the three SNPs was 0.82%, which is much lower than that explained by six SNPs [1.81% (or 0.35% in pregnant women in ALSPAC)] or eight SNPs [1.94% (or 0.37% in pregnant women in ALSPAC)]. The GRSs with three SNPs were associated with coffee consumption in non-pregnant women in the large UKBB but not with coffee consumption at gestational Week 32 in the smaller ALSPAC cohort, suggesting they are not good instruments for the ALSPAC analysis. However, analysis in ALSPAC showed that the GRS constructed of six SNPs had a strong association with coffee consumption in pregnancy (explaining 0.35% of the variance) and no association with drinking alcohol or smoking in pregnancy, suggesting that this set of SNPs might be the most appropriate to use in the context of coffee consumption in pregnancy.Power analyses suggest that UKBB has 80% power  to detect an effect of maternal coffee consumption equivalent to a 26.9-gram difference in birthweight per cup of coffee per day, or 0.03 more stillbirths per cup of coffee per day, if we conservatively assume that the coffee GRSs explain ∼0.37% of the variance in maternal coffee consumption during pregnancy. These asymptotic results and others suggest we have adequate power in our analyses to exclude large adverse effects of maternal coffee consumption on many pregnancy-related outcomes, but not the smaller magnitude causal effects that were estimated in this study. In this context it is also important to note we do not find strong evidence of an inverse effect of coffee consumption on birthweight, as previous observational analyses have suggested. Given our power calculations, we can be confident that a large inverse effect of coffee consumption on offspring birthweight is unlikely.,Lastly, although coffee is the primary source of caffeine in most populationsTaken together we have performed a large MR study using three different sets of genetic variants in three cohorts, with additional publicly available data. All of our analyses show similar results and suggest that if any adverse effects of coffee consumption on birthweight, gestational age, pre-term birth, stillbirth or miscarriage exists, it is likely to be small.In conclusion, we did not find strong evidence of an adverse causal relationship between maternal coffee consumption and birthweight, gestational age, the number of stillbirths, risk of pre-term birth or spontaneous miscarriages. Notably, a null association may be due to a lack of power and needs to be validated in even larger studies.This project received ethical approval from the Institutional Human Research Ethics committee, University of Queensland .dyac121_Supplementary_DataClick here for additional data file.


Epicardial cysts are rarer benign tumors than pericardial cysts. There have been few reports on surgical management of epicardial cysts. A 17-year-old normotensive boy presented with chest pain and palpitations, which on evaluation was found to be a mediastinal mass . Surgical resection of the cyst via thoracotomy was planned. The cyst was diagnosed as an epicardial cyst intraoperatively. However, due to the epicardial origin of cyst and posterior adhesions, resection was done via midline approach. The base was formed by visceral pericardium and eroding into myocardium of left ventricle, so the resection was concluded with on-pump surgery. In case of erroneous diagnosis or undesirable finding, a safer midline approach with on-pump surgery, as an alternative to minimally invasive approach for complicated epicardial cysts (erosion into ventricle/lying in close proximity to important structures or near to coronary arteries) should be considered. We hereby report a case of a giant epicardial cyst eroding into the left ventricle which simulated a pericardial cyst on preoperative assessment.A 17-year-old boy with no previous medical or surgical history presented with chest pain and off and on palpitations. Clinical examination revealed normal respiratory and cardiac examinations but elevated jugular venous pressure. Echocardiography revealed a large cyst (7×6.8×7 cm) around the posteroinferior part of mediastinum and extending laterally. Magnetic resonance imaging (MRI) revealed a well-defined cystic mass lesion in the posterior, inferior and lateral aspect of left cardiac border appearing hyperintense on short inversion time inversion recovery (STIR) sequences and hypointense on T1 sequence .Therefore, a pericardial cyst removal via small thoracotomy was planned. Thoracotomy was done but pericardium was found to be normal, except adherent posteriorly and superiorly, and the cyst appeared to be epicardial in origin. Therefore, we planned to proceed via median sternotomy with cardiopulmonary bypass (CPB). The cyst was found to be pushing the ventricles anteriorly. In addition, the mass was adhered to the pericardium and the base was formed by visceral pericardium and myocardium of the inferior wall of the left ventricle. The cyst was most tightly attached to the left ventricle inferiorly. Thus, it was thought to have originated from the posteroinferior portion of the left ventricle (LV). Dissection of the mass was difficult because of adhesions and proximity to the posterior descending artery.Cyst wall was thick and with feeder vessels over the surface . It was Histopathology revealed a single layer of mesothelial cells. In addition to blood and lymphatic vessels, smooth muscle cells, lymphocyte infiltration, and fibrosis were observed . The fol-3. Most are asymptomatic and found incidentally on chest radiographs. Seventy percent are located in the right cardiophrenic angle, 22% are in the left, and the remainder are in the anterior or posterior mediastinum. It is usually composed of a single layer of flat or cuboidal mesothelium containing a clear, yellowish fluid,5.Pericardial cysts are uncommon benign tumors, which account for 7% of all mediastinal tumors with an incidence of 1:100,000,6.Epicardial cysts are much rarer than pericardial cysts, and their surgical management has seldom been reported. The surgical indications are when the cyst becomes symptomatic, infected or possibly malignant, grows progressively and compresses important adjacent structures,3,7We suggest that the surgeon must be aware of the possible need for CPB in such situations.Herein, we report our experience with a posteroinferior epicardial cyst that was successfully resected with on-pump surgery. In our patient, excision was complicated because the cyst was in close proximity to the posterior descending artery. Resection followed by adequate evaluation and reinforcement of the thinned ventricular wall could not be accomplished without CPB. To avoid injury to the artery, we decided to operate with CPB support. CPB may be required when the cysts compress surrounding structures or erode the ventricular wall and coronaries. Although MRI is useful to differentiate cysts from other cardiac lesions, it also cannot differentiate between pericardial and epicardial cysts. This should broaden the spectrum of the potential appearance of differentials such as epicardial masses. The role of cardiac magnetic resonance in tissue characterization to avoid erroneous preoperative diagnosis may have diagnostic importance.Preoperative differential diagnosis between a pericardial cyst and an epicardial cyst is challenging because they cannot be differentiated on computed tomography (CT),2.Coronary CT or angiography might be considered especially with regard to the degree of adhesions and location of the coronary vessels. However, it may not always exclude the possibility of coronary involvement because some literature reported epicardial cysts with coronary vessel involvement and need for CPB to resect those cysts despite having negative findings.Video-assisted thoracoscopic surgery/thoracotomy may be the first option but when invasion of important structures, including the left ventricle and coronary artery is suspected, median sternotomy with CPB should be considered. Off-pump resection may be indicated for uncomplicated cystsIn our case, we were concerned about adhesions and proximity of the cyst to surrounding structures, thus the less invasiveness of the thoracotomy was not considered beneficial enough to outweigh the risks associated with inadmissible complications. Steady progression of the pathology and inflammation seem to be the reason for adhesions between the cyst and the pericardium. Surgical resection in CPB may be a better option when the cyst lies near important structures/erosion of the ventricular wall.The primary take-away lesson from our reported incidence is that, despite detailed preoperative investigation and assessment, misdiagnosis of cardiac masses cannot be completely ruled out and erratically may completely simulate another condition which can change the therapeutic approach. In such a situation, the surgeon should act patiently and should prefer an approach which can be best for the patient.


Blastocyst developmental speed, morphological grading and patient age are associated with pregnancy outcomes of frozen-thawed cycles. This study aimed to compare the clinical and neonatal outcomes between poor-quality D5 blastocysts and good-quality D6 blastocysts stratified by patient age.n = 723) received one D5 poor-quality blastocyst; group B (n = 900) received one D6 good-quality blastocyst. Pregnancy and neonatal outcomes were compared among the four groups stratified by 35 years of age.A total of 1,623 cycles were divided into two groups: group A (p > 0.05), but there was no statistical difference. The same trend was showed for patients aged ≥ 35 years . Moreover, when patients were in the same age category, there was no significant difference in terms of gestational age, birth weight, birth height, and rates of preterm birth, low birth weight, and very low birth weight between groups A and B.When patients were in the same age group, there was no significant difference in terms of age, body mass index, infertility duration, infertility type, fertilization method, proportion of endometrial preparation protocols, and endometrial thickness between D5 poor-quality and D6 high-quality blastocysts groups. Live birth rate of D5 poor-quality blastocysts was higher than that of D6 high-quality blastocysts for patients aged < 35 years (35.48% vs. 31.13%, e acceptable live birth rate.The preferential selection of poor-quality D5 blastocysts for transfer compared to high-quality D6 blastocysts is recommended, especially for advanced age patients. Single good-quality D6 blastocyst transfer can be considered for th Multiple embryo transfer has been preferentially performed to increase pregnancy outcomes for a few decades after the first baby was born using in vitro fertilization and embryo transfer technology (IVF-ET) . HoweverBlastocyst developmental speed is regarded as one of the important factors affecting IVF pregnancy outcomes. Many studies have shown that the pregnancy outcomes of day 5 (D5) blastocysts are significantly better than those of day 6 (D6) blastocysts in frozen embryo transfer (FET) cycles –9, and sThe blastocyst transfer strategy should also consider patient age, as live birth rate gradually decreases with age . In clinTherefore, this retrospective compared the pregnancy outcomes between poor-quality D5 blastocyst transfer and good-quality D6 blastocysts stratified by 35 years of age, and to determine whether single D6 good-quality blastocyst was adequately recommended for all populations undergoing IVF. We hope to provide additional references for selecting a more appropriate blastocyst transfer strategy that reduces multiple pregnancy rate without compromising the live birth rate.This was a retrospective cohort analysis of patients who underwent FET cycles at the Department of Reproductive Medicine of the Third Affiliated Hospital of Guangzhou Medical University between January 2014 and December 2020. The inclusion criteria were as follows: (i) aged 20–39 years; (ii) first IVF/intracytoplasmic sperm injection cycle, (iii) number of ET cycles ≤ 2, and (iv) endometrial thickness ≥ 7 mm on the initiation of progesterone exposure. The exclusion criteria were as follows: (i) blastocysts derived from vitrified or donated oocytes; (ii) preimplantation genetic testing cycles; (iii) stage III to IV endometriosis/adenomyosis; (iv) known uterine anomalies; and (v) untreated hydrosalpinx/uncontrolled systemic diseases prior to FET. Institutional review board approval was obtained from the ethics committee of the Third Affiliated Hospital of Guangzhou Medical University [Ethic no. (2022)-013]. The patients/participants provided their written informed consent to participate in this study.n = 723) received one D5 poor-quality blastocyst; group B (n = 900) received one D6 good-quality blastocyst. A total of 29 patients contributed two SBT cycles during the study period. The clinical and neonatal outcomes were analyzed among the four groups stratified by age using a cutoff of 35 years.The FET cycles that met the inclusion criteria were divided into four groups: group A (The patients in this study were treated with either gonadotropin-releasing hormone (GnRH) agonist or GnRH antagonist for pituitary suppression, as previously described . Briefly2, 5% O2 and 37℃. G-1™ plus  was used for cleavage stage embryos and G-2™ plus  for blastocyst stage. The quality of day 3 cleavage embryo was assessed about 68 h post insemination/injection, and the quality of blastocysts were evaluated on Day 5 about 116 h post insemination/injection or Day 6 about 140 h post insemination/injection.As previously described , fertiliBlastocyst morphological grading was assessed on day 5 or day 6 using the Gardner and Schoolcraft grading system , which dTwo main schemes for endometrial preparation in this study were applied according to clinical judgment and patient preference. Natural cycle was performed for patients with regular menstrual cycle. Ovulation was confirmed by transvaginal ultrasonography and serum hormone measurement. On the day of ovulation, the patient received 90 mg vaginal progesterone  once daily. In artificial cycles, 6 mg oral estrogen  daily was started on the second to fourth day of the menstrual cycle for one week and adjusted to 8–10 mg based on endometrial thickness and serum hormone levels. Vaginal progesterone  90 mg daily and dydrogesterone 10 mg twice daily were administered for endometrial transformation, as soon as the endometrial thickness reached ≥ 7 mm.The blastocyst transfer was performed on the sixth day after ovulation confirmation or progesterone exposure using a soft-tipped Wallace  catheter under ultrasound guidance. All the patients received progesterone for luteal support and continued at the same doses until 14 days after FET and up to 10 weeks of gestational age in cases of pregnancy.Primary outcome was live birth rate, and secondary outcomes included multiple pregnancy rate, clinical pregnancy rate, early miscarriage rate, and neonatal outcomes. Live birth was defined as the delivery of a live fetus after 28 weeks of gestation. Clinical pregnancy was defined as at least one intrauterine or extrauterine gestational sac confirmed by ultrasound at 6–7 weeks of gestation. Early miscarriage was defined as intrauterine pregnancy loss before 12 weeks of gestation. Preterm birth was defined as delivery of a viable infant before 37 weeks of gestation. Low birth weight was defined as a birth weight of less than 2500 g and very low birth weight as a birth weight of less than 1500 g.p < 0.05.All data were analyzed using Statistical Package for Social Science version 22.0 software . Student’s t-test was used for continuous variables, which were expressed as the mean ± standard deviation. The Fisher’s exact test or chi-square test, as appropriate, was used for categorical variables, which were described as frequencies and percentages. Statistical significance was set at A total of 1,623 FET cycles were included in this study from January 2014 to December 2020 and divided into two groups, depending on the blastocyst quality and developmental day. Two pregnant patients were lost to follow-up in this study. Clinical and neonatal outcomes were analyzed among these groups stratified by 35 years of age. The baseline patient characteristics are shown in Table The clinical outcomes of the patients between the two groups stratified by 35 years of age are presented in Table Comparisons of neonatal outcomes between the two groups stratified by 35 years of age are summarized in Table e acceptable pregnancy outcomes.This retrospective study is the first to compare the pregnancy outcomes between poor-quality D5 blastocysts and high-quality D6 blastocysts and to explore the transfer strategies of D6 high-quality blastocysts stratified by 35 years. We hope to provide more appropriate strategies for existing transfer strategies. Our results showed that the live birth rate of single poor-quality D5 blastocysts was higher than that of single high-quality D6 blastocysts, but the difference did not reach statistical significance for patients aged < 35 years (35.48% vs. 31.13%), and the same trend was observed for ≥ 35-year-old patients (29.09% vs. 21.28%). Additionally, single good-quality D6 blastocyst transfer can be considered for thp < 0.05), and the implantation competence was decreased in D6 blastocysts compared with D5 blastocysts when a total of 533 spindles were analyzed on days 5 and 6 vitrified-warmed blastocysts [SBT is an effective method for reducing the risk of multiple pregnancies. To evaluate whether patients are suitable for SBT, many factors that affect the pregnancy outcomes of blastocyst transfer cycles must be comprehensively considered, including age, blastocyst developmental speed, and morphological grading. Numerous studies have investigated the effect of blastocyst developmental speed on pregnancy outcomes and showed that the rates of ongoing pregnancy and live birth of D5 blastocysts were significantly higher than those of D6 blastocysts , 19, whistocysts .Another possible reason is that earlier blastocyst development is independently associated with a higher likelihood of embryonic euploidy, which supports the preferential selection of normally developing D5 blastocysts for transfer to improve pregnancy outcomes compared to growth-retarded D6 blastocysts among unbiopsied embryos , 24. Howp = 0.034), and similar trend also exists with blastocysts at the same developmental speed [In addition to aneuploidy testing and blastocyst development rate, blastocyst morphological grading is critical for selecting optimal embryos with a good development potential for implantation . For unbal speed . Therefop = 0.001) when patients were transferred with high-quality blastocysts in FET cycles [p < 0.0001) is independently associated with a lower euploidy percentage [To date, only a limited number of studies have explored transfer strategies for high-quality D6 blastocysts. A study by Kang et al. showed that D6-SBT produced significantly lower clinical outcomes compared with D6-DBT (23.4% vs. 51.6%, T cycles . Howeverrcentage . When blrcentage . Thereforcentage . For poorcentage . HoweverThere is no consensus regarding the effects of blastocyst developmental speed and morphological grading on neonatal outcomes. Previous studies have shown that D6 blastocyst transfer is associated with increased birth weight after FET compared with that in the D5 group , 30, butThis study had some limitations. First, it was a retrospective study design; however, the baseline characteristics of the patients among the two groups were not statistically different, indicating that the populations included in this study among these groups were similar. Second, there was a relatively inadequate sample size of live births, resulting from patients aged ≥ 35 years, and the results from women of advanced age need to be verified in further large population studies. Third, patients over 40 years of age were not recruited in this study, which may prevent generalization of the conclusions. The main strength of this study was that the FET cycles were specifically grouped based on a combination of morphological grading and blastocyst developmental speed, and data were analyzed among groups stratified by 35 years of age, which may help improve existing blastocyst selection strategies.Our results suggest that poor-quality D5 blastocyst transfer was preferentially selected over high-quality D6 blastocysts, especially for advanced patients. SBT of D6 good-quality blastocysts was recommended for the acceptable pregnancy outcomes.


Globally, hypertension is one of the main threats to public health and a significant risk factor predisposing individuals to various cardiovascular conditions. Hypertension in the young is particularly complex and challenging. Accumulating evidence has implicated that low birth weight is vital for elevated blood pressure, and birth weight was negatively correlated with blood pressure. However, fewer studies with conflicting results have addressed the associations between birth weight and blood pressure in children and adolescents, and there is no relevant research conducted in the NHANES population. The principal objective of this project was to investigate the relationship between birth weight and blood pressure in children and adolescents in NHANES.A total of 7600 subjects aged 8 to15 were enrolled in the present study from the National Health and Nutrition Examination Survey (NHANES) 2007–2018. Outcome variables were systolic blood pressure(SBP) and diastolic blood pressure(DBP). Birth weight was regarded as an independent variable. EmpowerStats software and R (version 3.4.3) were performed to examine the association between birth weight and SBP or DBP.p = 0.0013), especially in non-Hispanic White , aged between 13 to 15, and male individuals. However, there was no unidirectional association between birth weight and DBP in the fully adjusted model and in sub-analysis. An inverted U-shaped and J-shaped relationship was uncovered between birth weight and DBP in those aged 13 or above and Mexican Americans, respectively. The inflection point calculated by a recursive algorithm of birth weight in these groups was all 105 oz.Birth weight was negatively correlated with SBP in the fully-adjusted model(β = -0.02, 95%CI: -0.04 to -0.04, The current study identified that birth weight was negatively related to SBP but not significantly related to DBP in children and adolescents aged 8 to 15, highlighting different potential mechanisms behind high SBP and high DBP in the young. However, an inverted U-shaped and J-shaped relationship between birth weight and DBP was observed, suggesting that targeted intervention measures should be taken for different groups of people rather than generalizations. Hypertension, a global threat to human health, substantially increases the risk of cardiovascular diseases and is a prominent contributor to mortality with more than 1 billion cases . Along wHypertension is a multifactorial disorder with complex mechanisms and numerous causes arising from the interplay of lifestyles, living conditions, and genetic factors , 11. In However, the current research on the relationship between birth weight and blood pressure is partly controversial and even completely contradictory –17. Lai Additionally, fewer studies with conflicting results have addressed the associations between birth weight and blood pressure in children and adolescents, and there is no relevant research conducted in the NHANES population. Therefore, we proposed this study to investigate the relationship between birth weight and blood pressure in NHANES, which has tremendous clinical implications for promoting the health of adolescents and reducing the risk of cardiovascular disease in adulthood.The National Health and Nutrition Examination Survey (NHANES), a population-based survey conducted by the National Center for Health Statistics (NCHS), is a publicly used data set used to record the health status and related personal and lifestyle characteristics of all civilians in the United States. A multi-stage, complex clusters, probabilistic sample design is used for data acquisition and analysis to achieve a nationally representative rather than a simple random sample from the general US population . In partA total of 9094 subjects aged between 8–15 were enrolled in the primary analysis. The inclusion criteria were subjects who had self-reported birthweight with valid blood pressure records. We adhered to the following exclusion criteria:(1) individuals with missing birth weight or with invalid information; (2) those without blood pressure records;(3) those with self-reported severe diseases such as cancer and any other congenital diseases. The final sample size for analysis was 7600, after excluding the participants as mentioned above. The NCHS Ethics Review Committee supports this study, and each subject also signed a written informed consent .Blood pressure, including SBP and DBP, and birth weight were treated as dependent and independent variables, respectively. Proxy-reported birth weight data are only available for individuals aged 15 and under. Birth weight was recorded in pounds and ounces and converted into ounces in the final analysis. According to the World Health Organization (WHO) definition, low birth weight means that the birth weight is less than 2,500 g , which iIn addition, the following variables were collected and analyzed in the current study: age, race/ethnicity, gender, the ratio of family income to poverty, height, weight, body mass index (BMI), waist circumference, triglyceride (TG), total cholesterol (TC), LDL-cholesterol (LDL), plasma fasting glucose (FBG), uric acid (UA), creatinine (Cr), blood urea nitrogen (BUN) and glycohemoglobin. Also, associated risk factors, including the mother's age when the child was born, were also collected and analyzed. As BMI in the young varies with gender and age, we calculate age- and sex-specific BMI to evaluate weight status by using height and weight measurements gathered from the physical examination . We defiBlood pressure measurement procedure: After all subjects rested quietly for at least 5 min in the Mobile Inspection Center (MEC), the appropriate cuff was selected according to the size of the subject's upper arm. Three consecutive blood pressure readings will be obtained once the participant's maximum inflation level (MIL) is determined. If the measurement is interrupted or incomplete, or invalid, a fourth reading will be undertaken. An average value of all valid readings was served as the final blood pressure.Missing value management: We excluded subjects with missing independent or dependent variables. The missing continuous variables were replaced by the median. The missing categorical variables were regarded as a separate group.www.cdc.gov/nchs/nhanes/.Any detailed information about the variables acquisition process is described at We used the weighted analysis to obtain national representation following the NCHS Analysis Recommendation. The continuous variables were characterized by mean ± standard deviation, or median and interquartile range when appropriate. The categorical variables were presented as a percentage(%). The P-value was calculated using a weighted chi-squared test for categorical variables and a linear regression model for continuous variables. The association between birth weight and blood pressure, including SBP and DBP, was analyzed using multivariable linear regression. To further analyze the relationship between birth weight and SBP as well as DBP, we used the following three models: Model 1: No adjustment for variables; Model 2: Gender, age, and race/ethnicity were adjusted; Model 3: All underlying covariates including sex, age, race/ethnicity, ratio of family income to poverty, height, weight, BMI, waist circumference, TG, TC, LDL, FBG, UA, Cr, BUN, glycohemoglobin and mothers' age when born were adjusted.http://www.Rproject.org) and EmpowerStats software (http://www.empowerstats.com). The results would be considered to be statistically significant if a two-sided p-value of < 0.05.In addition to further data research, we subsequently performed subgroup analysis stratified by age, gender, and race/ethnicity. A weighted generalized additive model and a smooth curve fitting were conducted to address nonlinearity afterward. When nonlinearity was uncovered, we first calculated the vital inflection point using a recursive algorithm and then conducted a weighted two-piecewise linear regression model on both sides of the inflection point. The statistical analyses were performed using R software . In sub-analysis stratified by gender, age, race/ethnicity, this negative association was more obvious in males, and age >  = 13 years old and in non-Hispanic White   and sub-analysis stratified by gender, age, race/ethnicity(Table Contrastingly and unexpectedly, there was no linear association between birth weight and DBP in the fully adjusted model(β = -0.01, 95%CI: -0.03 to 0.02, Furthermore, we performed a weighted generalized additive model and a smooth curve fitting stratified by age, gender, and race/ethnicity to detect the nonlinear relation between birth weight and SBP as well as DBP and further confirm the results Fig. ,5,6,7,8.The present study utilized the population-based cross-sectional resources of NHANES to detect the correlation between birth weight and blood pressure in general children and adolescents aged 8 to 15, which, to our knowledge, was the first time to examine such a relationship in this population. We adjusted the socioeconomic conditions, physical measurement indicators, mother's age when born, and common predisposing risk factors for hypertension for all the participants. The major finding to emerge from the current study was that birth weight was negatively correlated with SBP even after adjusting for the relevant covariates, especially in White, aged between 13 to 15, and male individuals. However, there was no unidirectional relationship between birth weight and DBP. A somewhat unexpected finding is that for individuals aged between 13 to 15 and Mexican Americans, birth weight and DBP showed an inverted U-shaped relationship and an inverted J-shaped relationship, respectively.Globally, hypertension, responsible for the increasing burden of disease, is one of the main threats to public health and a significant risk factor that predisposes individuals to various cardiovascular conditions , 24. HypBarker et al.  first prThe following underlying mechanism may be involved in the reverse relationship between birth weight and blood pressure. Firstly, low birth weight caused by fetal dysplasia is a significant cause of increased blood pressure in later life. Low birth weight is considered an essential surrogate indicator of a poor and adverse intrauterine environment , 37. LatNevertheless, some studies have questioned the relationship between birth weight and blood pressure, and some scholars even draw contradictory conclusions –17, 42. Previous findings have revealed that birth weight was identified to be associated inversely with DBP in adults  and adolIn addition, we found that among participants at the age of 13 to 15 years and Mexican Americans, there was an inverted U-shaped and inverted J-shaped relationship between birth weight and blood pressure. Furthermore, these trends were not observed in those younger than 13, which may be related to different physical growth manner after the age of 13, such as changes in adolescent hormones, which requires further confirmation. Previous studies have found that different groups of people had different responses to blood pressure. For example, Keller G et al.  analyzedTo conclude, the current study identified that birth weight was negatively related to SBP but not significantly related to DBP in children and adolescents aged 8 to 15 during the NHANES 2007–2018. However, we observed an inverted U-shaped association between birth weight and DBP, with low and high levels being related to lower DBP in individuals aged 13 to 15. In addition, our current study indicates a reverse J characteristic curve between birth weight and DBP in Mexican Americans. It is well known that even a slight rise in blood pressure can increase the long-term risk of target organ damage and cardiovascular disease. Therefore, it is imperative to tease out the etiology of hypertension in the young and find potential preventive measures. Our findings have a number of profound implications in clinical practice. In the first place, our research supports the view that using precision medical measures to improve prenatal nutrition and growth to intervene in low-weight fetuses may improve cardiovascular fitness in adulthood. Secondly, for infants with low birth weight, standardized monitoring of blood pressure and timely intervention, such as nutrition and diet adjustments, may help reduce the risk of hypertension, exceptionally high SBP. Lastly, birth weight has different effects on DBP for different groups of people, suggesting that targeted intervention measures should be taken rather than generalizations.Nevertheless, this study still has the following primary deficiencies. First, this is a cross-sectional study, and the birth weight data reported by the agency may have some recall bias. Second, there is a lack of dynamic information regarding the impact of birth weight on adolescents' blood pressure. Finally, the absence of data about underlying confounding factors such as gestational age, puberty development, physical activities, and other unidentified prognostic factors was another flaw of the study. Our findings should be interpreted with caution, given the above limitations. Prospective studies examining infants and tracking their blood pressure in adulthood to verify the causal effect of birth weight on hypertension are imperative and urgent.