Several studies have demonstrated an increased risk of congenital hypothyroidism (CH) in girls in comparison to boys.The aim of this study was to determine the potential interactions that are able to change the effect of gender on congenital hypothyroidism.We conducted a matched 1:4 case-control study in Hamadan Province, western of Iran, from 2005 to 2011. Based on screening program data, neonates with TSH ≥ 10 mU/L and T4 ≤ 6.4 μg/dL were considered as congenital hypothyroidism (Cases). Cases and controls were matched regarding the year and place of birth. Data was analyzed using two different approaches including propensity score and multiple conditional logistic regression model.A total of 277 cases and 1036 controls were included in the study. Girls accounted for 57.4% of the cases and 51.2% of controls (P = 0.065). Based on the multiple conditional logistic regressions, only the interaction of gender (girl) and birth season (summer) increased the likelihood of CH significantly . On the other hand, the ORs of the interaction of gender and all other factors (except for birth season) were not statistically significant in CH.Birth season might act as an interaction that is able to increase the risk of CH in girls. Accordingly, awareness of the birth season could help policymakers who plan preventive programs to reduce the false negative results among neonates, especially girls. Congenital hypothyroidism (CH) is one of the most common congenital endocrine disorders classified into permanent and transient CH . NewbornNumerous epidemiological studies were conducted to investigate the risk factors of CH. Many studies reported that CH was associated with individual and environmental factors, including gender , birth wHormones are the basis of many biological differences between both sexes . AccordiTo our knowledge, this is the first study to assess CH risk factors among Iranian neonates by gender groups. We investigated the interaction between gender and other investigated factors to CH occurrence in neonates.This matched case-control study was part of an MSc thesis, approved by the local Human Subject Review Board of Hamadan University of Medical Sciences and conducted in Hamadan Province, western of Iran, in 2012. In Iran, neonatal CH screening program is primarily based on TSH measurement in filter paper blood spots, All of the neonates born in Hamadan Province between September 2005 and March 2011 were screened for CH between three to five days of age. Those with suspicious test results (TSH > 5 mU/L based on capillary blood collected from a heel stick and adsorbed onto filter paper) were tested for TSH and T4 and finally, the diagnosis of CH was confirmed by serum TSH ≥ 10 mU/L and T4 ≤ 6.4 μg/dL (Cases) . Sample In our study, we investigated only the effect of the potential risk factors with a significant association with CH in an unadjusted regression model . VariablTo consolidate the strength of our findings, we used two statistical methods to estimate the risk associated with CH. Firstly, we performed a propensity score matched logistic regression model. In this approach, we adjusted the models for other factors for minimizing the effect of other potential confounding factors in assessing each variable. We individually matched each case to one control based on the propensity score. Secondly, we constructed conditional logistic regression models to derive both unadjusted and adjusted odds ratios (OR) and 95% confidence intervals (95% CI) as well as interaction term to check any interaction between the two factors. In our analysis, one of the two factors was gender, which was checked with other factors one by one.Data processing and analysis were performed at 0.05 significance level using the statistical software Stata 11 .A total of 277 cases and 1036 controls were included in the study. Girls accounted for 57.4% of cases and 51.2% of controls . The neonates' mean birth weight were 3040.2 ± 725.5 gr and 2952.8 ± 704.2 gr in girls and boys, respectively (P = 0.027). According to univariate conditional logistic regression results, there were statistically significant associations between the risk of CH and the investigated factors including birth season (winter), prematurity, father’s education and smoking, maternal goiter and anemia, parents’ consanguinity, mother’s age, jaundice at birth, and the type of delivery. The same results were found with a series of fluctuation  in multiple conditional logistic regression when the gender variable was added to the model.The interactions were analyzed by using the multiple conditional logistic regressions including the interaction terms between independent variables and gender on CH occurrence. Based on this model, only the interaction of gender (girl) and birth season (summer) significantly increased the likelihood of CH . On the other hand, the ORs of the interaction of gender and all other factors on CH were not statistically significant. According to the results of both univariate and multiple conditional logistic regressions, there was no association between CH and gestational age, birth weight, and twin. The main finding of the present study was that birth season (summer) accompanied with girl gender increased the risk of CH although any of these factors had little effect on the risk of CH individually. Based on the univariate conditional logistic regression, our result are in agreement with Ordookhani et al.  findingsMany reports have indicated that CH is frequently found in girls , 11, 19.In a previous report, we proposed that several prognostic factors such as twin, birth season, maturity, jaundice at birth, birth weight, maternal age, maternal anemia and goiter, gestational age, delivery type, father’s education level and smoking status, and consanguinity might be the key factors underlying the relatively high incidence of CH in investigated neonates . AlthougResults of the present study indicated that odds ratio estimates of CH for investigated factors (except for birth season) did not differ substantially between girls and boys. This is in line with other researchers findings. Ng et al. found that there was no significant difference between girls and boys regarding gestation and birth weight in all etiological subgroups such as athyreosis and ectopia groups . On the It is unclear why girls have a higher incidence rate of CH than boys, while there is no difference in proportion of other risk factors between them. We do not know the underlying causes of this difference exactly. This study had some strengths and limitations. A main strength of this study was that cases were selected based on census method between 2005 and 2011, and four controls were individually matched for each case. To consolidate the strength of our findings we used two statistical adjusted methods to estimate the ORs as well. The primary limitation of the study was its small sample size in some subgroups. Moreover, we performed two different multivariate analyses to decrease the confounding, but residual confounding was still inevitable.Our findings indicated that birth season might act as an interaction to increase the risk of CH in girls. Accordingly, awareness of the birth season could help policymakers who plan preventive programs to reduce the false negative results among neonates, especially girls. Whilst the CH prevalence was higher among girls than boys, but its reasons deserve further investigations to be elucidated. These observations need to be validated in larger epidemiological studies.


The outcomes for women who give birth in hospital compared with at home are the subject of ongoing debate. We aimed to determine whether a retrospective linked data study using routinely collected data was a viable means to compare perinatal and maternal outcomes and interventions in labour by planned place of birth at the onset of labour in one Australian state.Birthplace in England study.A population-based cohort study was undertaken using routinely collected linked data from the New South Wales Perinatal Data Collection, Admitted Patient Data Collection, Register of Congenital Conditions, Registry of Birth Deaths and Marriages and the Australian Bureau of Statistics. Eight years of data provided a sample size of 258,161 full-term women and their infants. The primary outcome was a composite outcome of neonatal mortality and morbidity as used in the Women who planned to give birth in a birth centre or at home were significantly more likely to have a normal labour and birth compared with women in the labour ward group. There were no statistically significant differences in stillbirth and early neonatal deaths between the three groups, although we had insufficient statistical power to test reliably for these differences.This study provides information to assist the development and evaluation of different places of birth across Australia. It is feasible to examine perinatal and maternal outcomes by planned place of birth using routinely collected linked data, although very large data sets will be required to measure rare outcomes associated with place of birth in a low risk population, especially in countries like Australia where homebirth rates are low. Birthplace in England study was undertaken to compare perinatal and maternal outcomes and interventions in labour by planned place of birth at the onset of labour for women with low risk pregnancies using a composite primary outcome. The exclusion criteria used enabled this planned place of birth to approximate the planned place of birth at the onset of labour as closely as a retrospective dataset can allow, with all women in this cohort labouring spontaneously at ≥37 weeks gestation.The primary composite outcome was defined as an infant having any one of the following:– Stillbirth– Early neonatal death (<7 days)– Neonatal encephalopathy– Meconium aspiration syndrome– Brachial plexus injury– Fractured clavicle– Fractured humerusBirthplace in England study methodology. To determine the remaining components of the composite outcome the following ICD-10-AM codes from the birth as well as any subsequent admission within the time frame were searched in the APDC: neonatal encephalopathy (P91.6. P91.81), meconium aspiration syndrome (P24.0 and P24.9), brachial plexus injury , fractured humerus (P13.3), and fractured clavicle (P13.4). The primary outcome will be reported as incidence per 1000 births.Stillbirths or neonatal deaths (NND) were identified in the PDC, APDC, RBDM and ABS. Only NNDs that occurred within the first week following birth were included in line with the Women were classified into the three groups according to their planned place of birth at the onset of labour and the primary composite outcome for the neonate was used. An addiBirthplace in England study[Continuous data were summarised using means derived from t-tests or ANOVA. Chi-square analyses were conducted on contingency data. Logistic regression was undertaken with adjustments occurring for maternal age, gestational age in weeks at delivery and parity as in the nd study. For allBirthplace in England study[Data were analysed with IBM SPSSv.20® with statistical significance established at the p < 0.005 level. The cohort of women identified as complicated were those who had pre-existing or pregnancy related hypertension or diabetes as recorded on the PDC or had either an antenatal admission or a birth admission (as recorded on the APDC) which included the ICD-10-AM codes O14.0, O14.1, O14.2, O14.9 (proteinuric hypertension), O15.0 , O10.0, O10.1, O10.2, O10.3, O10.4, O11 or O10.9 (chronic hypertension), O13.0 , O24.0, O24.1, O24.2, O24.3 (Type I or Type II diabetes) or O24.4, O24.9 . Women who had prolonged rupture of membranes were identified from the APDC utilising the codes O42.1 and O42.2 as were women who had experienced an antepartum haemorrhage . These were the same measures of morbidity as in To ensure accuracy of pregnancy classification, the birth and subsequent admissions of all women and babies which resulted in either a stillbirth or a NND were searched per data line. If a pregnancy complication or a pre-existing complication  was noted on any woman’s record her case was coded as complicated if it was not already so.In total, 258,161 women and neonates were included in the analysis. The majority of women  had their planned place of birth recorded as in a hospital labour ward, with 5.6%  in a birth centre and 0.3% (n = 742), planning a homebirth. There were differences in the demographic characteristics of the women in the three groups. Women who planned homebirth were more likely to be older  = 5.23) than those in the labour ward group  or those in the birth centre  and less likely to be primiparous (42% versus 63% and 62%) (p < 0.001) (Table Birthplace in England study. There were four babies with adverse outcomes identified in this group (two of these were >42 weeks and one >41 weeks). Three of the four babies were born in hospital. These babies were admitted to a Neonatal Intensive Care Unit or Special Care Nursery for between two and eleven days. Following this, they were all discharged alive and not readmitted. Babies of multiparous women were significantly less likely to experience the primary outcome in the birth centre setting  compared with in the labour ward. For multiparous women, the incidence of the primary outcome in the homebirth group was similar to the birth centre group , but with no statistically significant difference for nulliparous women   transferred from home to a labour ward or operating theatre Table . NullipaWomen in the homebirth and birth centre groups were significantly more likely to have a spontaneous vaginal birth (97% vs 86%) compared to the labour ward group (74%) and less likely to require an instrumental vaginal birth (4% and 9% compared with 16%) or an intrapartum caesarean section (3% and 5% compared with 10%)  and no episiotomy. Women who planned to give birth in a birth centre or at home were significantly more likely to have a normal labour and birth compared with women in the labour ward group Table . This waThe aim of our study was to determine firstly, whether a retrospective linked data study was a viable alternative to such a design using routinely collected data in one Australian state and secondly, to report on the outcomes and interventions for women (and their babies) who planned to give birth in a hospital labour ward, birth centre or at home.Birthplace in England Study. In order to fulfill this endeavour, we were limited to the outcomes from the study.This study was exploratory in nature – we undertook this analysis on data from the most populous state in Australia to establish that the approach was feasible before expanding it to the whole country. Therefore, we did not undertake sample size calculations and recognise that the study is underpowered to draw conclusions about homebirth and rare perinatal outcomes. This study aimed to determine whether a retrospective linked data study using routinely collected data was a viable means to compare perinatal and maternal outcomes and interventions in labour by planned place of birth in one Australian state using the composite primary outcomes outlined in the It is important to note that in all instances where we mentioned a lack of statistical significance in comparisons between the three groups we had ≤40% statistical power to detect any true differences. The small number of women choosing to give birth at home in this analysis reflects the Australian context. For example, in the most recent data from NSW, 95.5%  of women planned to give birth in a hospital labour ward, 3.7%  planned to give birth in a birth centre and only 0.3% n = 264) planned to give birth at home[4 plannedBirthplace in England[n England calculatn England. Given tThe study has demonstrated that, despite the sample size limitations, it is feasible to undertake a planned place of birth study using routinely collected linked data. There are considerable resource implications of using routinely collected data especially as such analyses can be repeated relatively quickly at different time points to track trends. Using linked data has added advantages. Linking datasets improves accuracy as well as provides a more comprehensive picture of the medical history and any events after the birth.There are disadvantages of using routinely collected linked data compared with specifically collected prospective data. While population health databases are an easily accessible and available resource, they were not designed to answer a specific research question, especially one applied retrospectively. There aThis analysis could only use data which was included in the datasets and hence could be linked. It is possible that there were unreported homebirths in NSW during this time period and these could not therefore be linked. Nonetheless, it is likely that these numbers are very small and were more likely not to have been attended by midwives (freebirths).Birthplace in England study. Composite indicators in population health datasets are becoming more common. In one recent study from the same state, NSW, a Neonatal Adverse Outcome Indicator (NAOI) was found to be able to reliability identify infants with a severe neonatal outcome and could be a useful way to monitor trends in maternity care in a cost effective manner[We used a similar composite neonatal outcome to the e manner.Birthplace in England study which is reassuring but validation work on the accuracy of intended place of birth and onset of labour would be valuable. Actual place of birth is accurate as it is a retrospective outcome.A further issue is that the planned place of birth variable as recorded in the PDC cannot be guaranteed to equate to the planned birth of birth at labour onset. Women who choose to give birth at home or in birth centres are on the whole strongly committed to this birth choice and where there are no complications, as is seen in this cohort, women are unlikely to change their minds after 37 weeks. Taking a term gestational age (37weeks) as intended place of birth also reduces the problems seen in previous studies with choice of birth place documented at booking. The outBirthplace in England study not to include inductions of labour it was not always possible to determine whether induction of labour, previous caesarean section and known group B strep carriage could be identified or reliably inferred from the data for 2008. The data collection form for the study was modified in 2009 to capture data on induction of labour and previous caesarean section[While it was the intention of the Birthplace in England study recruited 16,840 women planning to give birth at home at the onset of labour. Even in an 8-year time period, we were only able to include 742 women planning to give birth at home at the same time point. Nonetheless, the study provides the largest analysis of planned homebirth and birth centre births at the onset of labour in Australia and as such provides valuable evidence to assist the development of services and to support the need for ongoing data collection and research.The second aim of the study was to determine the outcomes for term babies according to planned place of birth. In Australia, homebirth is a much less common choice than in many other countries due to a combination of access, cultural history and professional support. This meBirthplace in England study. The neonatal outcomes for women giving birth centre or a labour ward were comparable although the levels of intervention were higher in the labour ward groups despite similarities in demographic and obstetric predictors.Our analysis, despite the sample size limitations, suggests that women planning to give birth at home, hospital or in a birth centre can expect to have good outcomes. The analysis by parity indicated that there were no statistically significant differences in adverse neonatal outcomes for nulliparous women although the numbers are much smaller than the Birthplace in England study where multiparous women who chose to give birth at home had favourable outcomes and less perinatal interventions[Multiparous women had good outcomes regardless of planned place of birth. However, there was significantly less intervention for this group with no apparent differences in neonatal outcomes suggesting that it is reasonable to support home as a place of birth for multiparous women. Similar findings were found in the ventions.Birthplace in England Study methodology is the much higher incidence of women >42 weeks in the homebirth group. Two out of the four adverse events in the homebirth group were associated with women who were > 42 weeks and one was >41 weeks. One could argue pregnancy beyond 42 weeks is not low risk and hence should not be included in the low risk group. Women who choose to give birth at home and in birth centres tend to want a more natural approach to labour and birth and are more likely to avoid intervention. The question that needs to be asked is whether this a reflection on the safety of place of birth or the different choices women make in these models of care. It would be worthwhile keeping this in mind in future studies.Another issue raised by following the Transfers during labour from home or birth centre to hospital require further analysis. Further research needs to be undertaken to determine why the high transfer rates were seen and to what extent these contribute to the higher, non-significant rates, for nulliparous women. It would be important to understand whether these rates are related to inadequate counseling or inadequate screening or a combination of factors.This analysis cannot distinguish between type of provider. For example, it is not possible to determine whether the homebirths were part of a publicly-funded homebirth program or attended by privately practising midwives. There are currently four publicly-funded homebirth programs in NSW although most were established post 2006 which means they would not have contributed large numbers of women to this cohort. PrivateThis study has demonstrated that it is possible to study the outcomes of planned place of birth using routinely collected linked data. Despite its limitation in sample size, especially for homebirth and rarer outcomes, the study provides important information that could inform the development, data collection processes and evaluation of different places of birth across Australia. Very large data sets will be required to measure rare outcomes associated with place of birth in the low risk population, especially in countries like Australia where homebirth rates are low.Ethical approval was obtained from the NSW Population and Health Services Research Ethics Committee, Protocol No. 2010/12/291.ABS: Australian Bureau of Statistics; APDC: Admitted patient data collection; CHeReL: Centre for health record linkage; NICU: Neonatal Intensive Care Unit; NND: Neonatal death; NSW: New South Wales; PDC: Perinatal data collection; RBDM: Registry of births, deaths and marriages; RCC: Register of congenital conditions; SCN: Special care nursery; VBAC: Vaginal birth after caesarean.The authors declare that they have no competing interests.The Birthplace in New South Wales Pilot Study was formulated by The Birthplace in Australia Chief Investigator Committee which includes all authors. CH and HD conceived of the study design, and wrote the first draft of the paper. HD and CT acquired the data and undertook the analysis and contributed to the content and editing. DS provided post-hoc calculations and contributed to the content of the paper. DE, JO, MF, HM, DF and VS contributed to the content and editing of the paper. All authors agree with the final draft and accept responsibility for the content of the paper.The pre-publication history for this paper can be accessed here:http://www.biomedcentral.com/1471-2393/14/206/prepub


Callithrix jacchus), allows us to model the effects of varying intrauterine environments  on the risk of losing fetuses in adulthood. Our previous work has characterized the fetuses of triplet pregnancies as experiencing intrauterine nutritional restriction.The impact of the intrauterine environment on the developmental programming of adult female reproductive success is still poorly understood and potentially underestimated. Litter size variation in a nonhuman primate, the common marmoset monkey . Regardless of their own birth weight or the sex ratio of the litter the experienced as fetuses, triplet females lost more fetuses than did twins. Females with a male littermate experienced a significant increase in the proportion of stillbirths.These striking findings anchor pregnancy loss in the mother’s own fetal environment and development, underscoring a "Womb to Womb" view of the lifecourse and the intergenerational consequences of development. This has important translational implications for understanding the large proportion of human stillbirths that are unexplained. Our findings provide strong evidence that a full understanding of mammalian life history and reproductive biology requires a developmental foundation. Developmental programming theory suggests that the intrauterine environment – the intersection of maternal ecology and fetal development Fetal number is another source of variation in the quality of the intrauterine environment that may have intergenerational effects. One of the classic life history tradeoffs is the balance between number and quality of offspring Callithrix jacchus), like all marmosets and tamarins  overall and according to litter size and birth weight, and then explores the relationship between a female marmoset’s birth condition  and her risk of pregnancy loss in adulthood.This paper first characterizes reproductive parameters in a colony of captive common marmoset monkeys  and adult reproductive parameters were known. Analyses were conducted on subsets of this group (i.e. twins and triplets). Adult females were housed with at least their adult male mate, but often with older offspring. It is not uncommon for the family group to contain adolescent, juvenile, and infant offspring at the same time. Family structure at the time of each pregnancy studied was not recorded and thus could not be considered in this study. Groups were housed according to Institutional Animal Care and Use Committee standards for marmosets.in utero and/or no lung flotation; DIU (“dead in utero”), meaning a mostly or fully developed fetus either aborted or discovered at term delivery but showing clear evidence of in utero death preceding labor ; and ABORT, meaning found or delivered before due date , and total lost litters , all fitted as continuous variables. We controlled all regression models for birth weight, birth year (to control cohort effects), and early adult weight. As described by Tardif and Bales Although litter size ranges from 1–5 in the captive common marmoset, analyses were restricted to twins and triplets because these are by far the two most representative litter sizes of origin of those females who survived to the age of maturity. All analyses were conducted using Stata for Windows, version 10 IC . Two-tailed T-tests were used to compare twins and triplets to each other in terms of birth condition and other life history characteristics. Z-tests were used to test the significance of the difference in proportion of fetal losses between twin and triplet females. There were nine pairs of females  in the sample who were born into the same litter. We used two-tailed T-tests to compare females with and without littermates in the study in terms of birth condition and the other life history characteristics.estat VIF command in Stata to measure the variance inflation factor. Models returning a VIF of >5 (indicative of high collinearity) were subject to rejection; none of our models returned a rejectable VIF.In some cases we wanted to evaluate the predictive relationships between litter size and pregnancy loss variables; therefore, we used simple and multiple linear regression modeling. We assigned all females a litter ID  and ran that ID as a random effect in regression models. We assumed that many of our predictor and outcome variables in these models would exhibit collinearity. Therefore, all models were evaluated for collinearity using the Raw data are stored in databases at the SNPRC and the University of Illinois at Chicago. Requests for data can be directed to the primary author.At the time of these analyses, there were 1395 animals in the Southwest National Primate Research Center marmoset colony database; a large proportion of this number includes animals that died before juvenility. Of adult animals, 113 were reproducing females. Not all females were born in the colony or entered the colony with birth data, so litter size at birth was known for 79 of these females, of which 75 were either twins (n = 37) or triplets (n = 38). These 75 females accounted for 94.95% of the reproducing females of known litter size at birth; remaining analyses are thus restricted to these twin and triplet females. When restricted to twin and triplet females of known birth weight and early adult weight, the sample size for analysis was 62  did not differ from the rest of the sample (n = 42) in litter size, birth weight, or adult weight; they had significantly fewer male littermates than the rest of the sample . TripletTwins and triplets did not differ in their age at first reproduction, nor did they differ in the number of litters produced or the total number of offspring gestated . TripletDespite the lack of difference in total offspring gestated, triplets lost three times as many offspring during pregnancy . TripletA multiple regression model including a female’s own litter size, birth weight, early adult weight, and birth year significantly predicted her rate of total loss, explaining 19% of the variance  model 1.in utero, compared to triplets who had 1.22 brothers  adolescent girls have been reported to exhibit reduced ovarian dimensions in utero have a longer anogenital distance (AGD) which is considered a masculinized phenotype Sry gene, the Y-linked zinc finger protein gene (ZFY), or both in utero cannot be ruled out. At this point it is also entirely unknown whether or the extent to which placental androgens differ in mixed sex marmoset litters.Transfer of prenatal testicular androgens to female fetuses as a function of mixed sex litters is a key factor driving differential reproductive development in several mammalian species. For example, female mice flanked by brothers in utero may indeed have an effect on a female’s reproductive development in the marmoset monkey. Although we did not have direct measures of androgen levels, we observed that females who shared the womb with any brothers were significantly more likely to lose offspring during gestation, with loss rates threefold greater than those females from all female litters. In our sample, this effect is most apparent in twins. Twin females lost significantly more offspring in adulthood when they shared the womb with a brother instead of a sister. The existence of a “brother effect” on twin female marmosets is potential evidence for an organizing effect of testicular androgens. If this is the case, then it is reasonable to expect that triplets would exhibit a higher degree of loss with increasing potential exposure to brothers in utero. However, the effect on triplet females was not significant, regardless of the number of male littermates. Our sample size may be inadequate to tease out a “brother effect” in triplets. There were only four all-female triplet litters, compared to the even distribution of male-female and female-female twin litters, precluding appropriate statistical testing of differences.The results of the current study further suggest that male exposure The pattern thus far elucidated hints that disordered reproductive development leading to pregnancy loss in triplet marmoset females is severe. It is important to note that among mammals, primates are unique in having what is called the fetal zone of the adrenal gland, which actively produces the androgens dehydroepiandrosterone (DHEA), DHEA-sulfate (DHEA-S), and androstenedione during gestation Developmental processes may underlie the large proportion of unexplained stillbirths in humans. Stillbirth is characterized as a multifactorial outcome with various risk factors contributing in large and small ways to an overall risk profile that varies widely across populations. Common maternal predictors of stillbirth in high-income countries include prepregnancy obesity, diabetes, chronic hypertension, infection, smoking, increasing maternal age, and lack of prenatal care sensu stricto stillbirth  so that losses span both the embryonic and fetal periods. In our planned prospective studies, specific temporal categories of loss will be employed. A third consideration is the impact of secular trends in birth weight, litter size, and adult weight on reproductive parameters. Individuals are being born at greater weights into larger litters and growing into larger adults than they were during the early years of the colony. The differential effects of litter size and birth weight reported here are independent of cohort effects, suggesting they are robust phenomena unaffected by secular trends; this strengthens the observation that developmental programming operates across a range of birth weights. Finally, our focus is on the influence of a female’s own early life characteristics on her adult reproductive function. The influence of the female’s mate was not considered in this study. Although paternal contributions such as age, sperm quality, and parental care are important to reproductive success and fetal outcomes, they were beyond the scope of the current study. Future analyses of such contributions and their impacts are planned.There are potential limitations of our study. First, though the marmoset is an anthropoid primate with many similarities to humans, the fact that it produces multiples as a matter of course differentiates its reproductive physiology from that of the human, typically a producer of singletons. The genetic mechanisms of litter size in marmosets are beginning to be elucidated, with potential for understanding multiple births of both natural and assisted origin in humans In summary, our data overall clearly show that fetal development has a tremendous impact on adult reproductive function: triplets lost three times as many fetuses as did twins. A female common marmoset monkey’s own litter size at birth – a phenotype reflective of a nutritionally or otherwise stressed fetal environment – acts on her ability to successfully gestate fetuses to term, perhaps via the development of the HPO axis and reproductive tract. This may be due to a combination of changes in nutritional allocation and prenatal androgen exposure, both of which may alter developmental pathways. We suggest there are specific developmental mechanisms that entrain reproductive phenotypes and life history schedules across generations, providing a novel way of framing life history plasticity and evolution in litter-bearing mammals. While there are obvious applications of our work to life history studies of litter size and the physiology of multiple pregnancies, the broader implications of our marmoset model transcend these phenomena, situated in the ability to model a naturally-occurring “developmental programming” or “growth-impaired” phenotype (triplets) compared to a “normal” or “control” phenotype (twins). Our findings provide strong evidence that a full understanding of mammalian life history, reproductive biology, and pregnancy outcomes requires a developmental foundation.Table S1Sample characteristics of females with and without littermates in the study.(DOCX)Click here for additional data file.Table S2Sample characteristics, stratified by birth weight.(DOCX)Click here for additional data file.


The use of a single national figure fails to capture the complex patterns and inequalities in early childbearing that occur within countries, as well as the differing contexts in which these pregnancies occur. Further disaggregated data that examine patterns and trends for different groups are needed to enable programmes to be focused on those most at risk. This paper describes a comprehensive analysis of adolescent first births using disaggregated data from Demographic and Household surveys (DHS) for three East African countries: Uganda, Kenya and Tanzania.The study initially produces cross-sectional descriptive data on adolescent motherhood by age , marital status, wealth, education, state or region, urban/rural residence and religion. Trends for two or more surveys over a period of 18–23 years are then analysed, and again disaggregated by age, wealth, urban/rural residence and marital status to ascertain which groups within the population have benefited most from reductions in adolescent first birth. In order to adjust for confounding factors we also use multinomial logistic regression to analyse the social and economic determinants of adolescent first birth, with outcomes again divided by age.In all three countries, a significant proportion of women gave birth before age 16 (7%-12%). Both the bivariate analysis and logistic regression show that adolescent motherhood is strongly associated with poverty and lack of education/literacy, and this relationship is strongest among births within the youngest age group (<16 years). There are also marked differences by region, religion and urban/rural residence. Trends over time show there has been limited progress in reducing adolescent first births overall, with no reductions among the poorest.Adolescent first births, particularly at the youngest ages, are most common among the poorest and least educated, and progress in reducing rates within this group has not been made over the last few decades. Disaggregating data allows such patterns to be understood, and enables efforts to be better directed where needed. The importance of the adolescent fertility rate (AFR) as a measure of a nation’s reproductive health is highlighted by its choice as an indicator within the Maternal Health Millennium Development Goal (MDG). Each year, an estimated 16 million girls and young women give birth between the ages of 15 and 19 , most of whom live in low or middle income countries [a wealth quintiles, education, region, religion and marital status at birth for Kenya, Tanzania and Uganda. As well as highlighting the importance of including socio-economic, cultural and geographic factors within any comprehensive framework for measuring and monitoring progress in reducing adolescent births, the focus on disaggregated data by age offers a further new dynamic for assessing progress in reducing adolescent fertility: there is some evidence that younger adolescents may face greater risks of poor health outcomes compared to older adolescents, so progress in reducing births in this group is particularly important [This paper provides detailed analysis on adolescent first births disaggregated by age mportant , 3. In amportant –6. The sFor the cross sectional data, the most recent DHS is used for Kenya, Uganda and Tanzania, . Initially, cross tabulations were created to ascertain the percentage of women aged 20–24 at time of survey who had their first birth at age less than 16, 16/17 and 18/19, disaggregated by place of residence, marital status at time of giving birth, region, religion, and wealth quintile. Sample weights were applied as necessary to account for differential chances of selection into the sample. For some of the analyses asset scores and quintiles were recalculated separately for urban and rural populations: this overcomes the problem inherent in joint analyses where assets may have different impact in urban and rural settings, and enables us to examine inequities within urban and rural environments separately. The index was constructed using principal component analysis to assign indicator weights using the same process as used by DHS/Macro [Trend data for adolescent first birth disaggregated by age, urban/rural residence and wealth are taken from DHS datasets covering a period of 18–23 years. Annual percentage rates of change are calculated. The period used to measure trends by wealth is shorter as asset indices were not introduced in DHS until the mid to late 1990s. We did not disaggregate wealth quintiles by urban/rural residence for trends as relatively small samples sizes made trends somewhat difficult to interpret.While bivariate approaches are valuable in identifying general patterns of socio-economic inequalities and identifying vulnerable groups, interpretation can be difficult as many of the potential explanatory factors are closely correlated. Multinomial multivariate logistic regression is therefore also carried out to predict first births in age groups under 16, 16/17 and 18/19, with women who did not give birth before aged 20 as the comparison group. In order to ensure consistency the analysis used women aged 20–25 years at the time of the survey in this analysis, but in order to check the robustness of the model the analysis was also run on a larger survey of women aged 20–29. This method enables us to determine whether the determinants of early adolescent first birth (<16 years) are different to those for first birth in later adolescence (16/17 years and 18/19 years). The models include variables for urban/rural residence, region , religion (Kenya and Uganda only: data was not collected for Tanzania), wealth and literacy level. Due to the fact that some girls who gave birth very early would not have reached the age where secondary school commenced prior to giving birth, further more disaggregated variables for education were not used.Table Table As expected, there is a marked economic gradient for women who have a first birth in adolescence. Table When we present wealth quintiles separately for urban and rural Figures  and 2, wIn all three countries a very high proportion of women report their first birth in adolescence among those who have had no education or only primary education Table . Again tFigure Data on religion are only available for Uganda and Kenya. In Uganda Muslims have a somewhat higher percentage of adolescent first births compared with the Christian religions, and this is most marked in the <16 age group . In Kenya the poorest four quintiles and poorest three quintiles have significant ORs for age groups <16 and 18/19 respectively, but no quintiles were significant for the 16/17 age group. In Tanzania all four poorer quintiles are all associated with large and significant increased OR of birth <16, but no quintiles are significant for the 16/17 age group and quintile 4 alone is significant for the 18/19 age group.When literacy is considered, in Uganda and Tanzania ORs are large and significant for women who cannot read or can only read part of a sentence. There is a clear pattern of higher ORs for the risk of giving birth <16 compared with 16/17 and 18/19. In Kenya the pattern is similar, except the OR is not significantly increased for women who cannot read for births at age 16/17.Rerunning the analysis using a larger sample of all women aged 20–29 at the time of survey produces very similar patterns . The pattern for wealth was clearer for this sample than for the 20–24 age group: in all three countries a greater number of wealth quintiles were associated with increased risk of birth for all age groups, and there was a clear pattern of ORs being larger for the equation with births under aged 16 as an outcome.In summary, wealth, education and region are all significantly associated with increased odds of an adolescent first birth compared with no adolescent first birth. The same variables are broadly significant when we consider births <16 years, 16/17 years and 18/19 years, but there tends to be a pattern of ORs being greater for the risk of births <16 years.In all three countries, and particularly in Uganda, a significant proportion of women (7-12%) still report that their first birth was before the age of 16 years. This is concerning, particularly as trends suggest that little progress in reducing births in this youngest group has been made over the last few decades. These girls are likely to be the most vulnerable: a higher proportion are poor, and are more likely to have received little or no education than older adolescent mothers. They are also less likely to be married, which, while not uncommon, in the context of East Africa may carry considerable stigma and lead to social exclusion .It is estimated that up to around 2.5 million births occur to girls aged under 16 years in developing countries each year . HoweverThe relatively large number of very early adolescent births, coupled with the potential increased risks faced by both mother and baby strongly points to the need for sexual and reproductive health programmes to be targeted at younger adolescents. However the needs of this group have been largely ignored. Girls in many developing countries are now maturing physically at an earlier age  and in TThe study suggests a strong relationship between education and literacy, and adolescent motherhood. This has been well recognised in earlier studies , 22, butThe very strong ORs in the multivariate analysis for region even after adjusting for urban/rural residence, literacy and wealth are likely to reflect the considerable ethnic diversity within these countries and suggest that there may be strong cultural driver for adolescent fertility. Programmes will need to understand and incorporate the cultural context, and work with local communities and key opinion leaders in order to plan and implement effective and tailored interventions. A review of successful programmes to reduce the risks of pregnancy and other adverse sexual health outcomes highlight the needs for the involvement of both the community and adolescents themselves in developing culturally sensitive interventions .The data on trends suggests modest declines in adolescent first birth for Kenya and Uganda, but not Tanzania. This period coincides with increasing contraceptive use among adolescents aged 15–19 in all three countries . HoweverData on trends suggests that the greatest progress has been made amongst the wealthiest: in fact there is some evidence that the percentage of women in the poorest quintile reporting adolescent first births has actually increased. Similarly far greater progress has been made in reducing adolescent first births in urban than in rural areas . This means that over time adolescent mothers are likely to become increasingly concentrated amongst poor, which may create further marginalisation and disadvantage. Targeted programmes are needed to reduce adolescent pregnancies amongst the most vulnerable, yet often large scale programmes fail to acknowledge the socio-economic dimension of adverse reproductive health outcomes, and out of school youth are poorly served . Programvice versa. Indeed in all three countries a significant proportion of women report the time of marriage within nine months prior to their first birth. Also the definition of how marriage or union is defined may differ: the DHS definition is broad, and includes legal and “traditional” marriages, as well as consensual unions with cohabitation. A fuller understanding of both the context and definition of marriage or unions within different sectors of the communities is important in planning interventions, and will require more detailed qualitative research to understand the association between marriage and adolescent births.In the three countries between a half and three quarters of women report they are married at the time of their first adolescent birth. Thus a proportion of these pregnancies may be driven by traditional practices and norms, and encouraged and sanctioned by families and the wider community. While this suggests approaches to reducing pregnancies adolescents may require integration with interventions to reduce early marriage it must be acknowledged that within the East African context, sexual activity prior to marriage is common, so marriage may be driven by pregnancy rather than It is worth noting that this study has a number of limitations. Cross-sectional studies using retrospective data of this type are unable to establish causation, and in particular it is impossible to establish with any certainty the extent to which the association between adolescent first birth and poor socio-economic indicators is a determinant or a consequence. DHS are generally considered among the best sources of data on adolescent sexual health, but fertility data are known to be affected by recall issues, including possible backdating of births to avoid completing the child module (which is only requested for children born less than five years before the survey date). In addition as adolescent pregnancy may be sensitive in some cultures it may be affected by the social desirability bias that is known to affect data on adolescent sexual activity . Very eaThese statistics do not include pregnancies that do not end in live births. Data are available within DHS for miscarriages, stillbirths and abortions, but there is clear evidence it is unreliable, with significant under-reporting , 30. An This study highlights the need for further research on the context and experience of adolescents who become mothers in order to inform policy and practice. There is particular need for more comprehensive research on particularly vulnerable groups to identify risk factors and develop interventions: these include the poorest , very young adolescents, and those not in school. Specific focus is needed on the potential increased risks associated with personal or household circumstances, such as those living in single parent families , orphaneThe development of more nuanced and disaggregated data is of considerable relevance for the post 2015 global agenda, and is particularly relevant in light of the broad focus on reduction of inequities in the Sustainable Development Goals (SDs) . AdolescThis paper highlights the inequity in adolescent early first births in East Africa and the diversity within countries, and stresses the need for more disaggregated data to plan programmes and monitor progress. It also notes a concerning lack of progress in reducing adolescent pregnancies among the poorest and those in rural areas, and points to a need for greater focus on reaching the most vulnerable - very young adolescents and those who are poor or have little or no education – with effective interventions and support.aIt was decided to use a cut-off of <16 as the youngest grouping as there is some indication that this may be the age below which maternal and neonatal outcomes are most adversely affected5,6.SN is a British Academy Postdoctoral Fellow within the Department of Social Statistics and Demography at the University of Southampton. VCM and DC work for the World Health Organization.


To analyze if dietary patterns during the third gestational trimester are associated with birth weight. Longitudinal study conducted in the cities of Petropolis and Queimados, Rio de Janeiro (RJ), Southeastern Brazil, between 2007 and 2008. We analyzed data from the first and second follow-up wave of a prospective cohort. Food consumption of 1,298 pregnant women was assessed using a semi-quantitative questionnaire about food frequency. Dietary patterns were obtained by exploratory factor analysis, using the Varimax rotation method. We also applied the multivariate linear regression model to estimate the association between food consumption patterns and birth weight.farofa/grits, pizza/hamburger/deep fried pastries, soft drinks/cool drinks and pork/sausages/egg), which accounts for 6.9% of the variance; and (4) snack pattern , which explains 5.7% of the consumption variability. The snack dietary pattern was positively associated with birth weight  in pregnant adolescents. Four patterns of consumption – which explain 36.4% of the variability – were identified and divided as follows: (1) prudent pattern , which explained 14.9% of the consumption; (2) traditional pattern, consisting of beans, rice, vegetables, breads, butter/margarine and sugar, which explained 8.8% of the variation in consumption; (3) Western pattern (potato/cassava/yams, macaroni, flour/ For pregnant adolescents, the greater the adherence to snack pattern during pregnancy, the greater the baby’s birth weight. When data were not available, we analyzed child booklets or certificates of born alive.The following variables were evaluated: (i) sociodemographic: age of pregnant women, marital status , self-referred skin color , education level according to years of study, work outside home , economic class ; (ii) tobacco ; (iii) self-referred chronic diseases: arterial hypertension , diabetes mellitus ; (iv) obstetric antecedents: parity , prior history of perinatal death, low birth weight or prematurity; (v) maternal nutritional status , and (vi) adequacy of prenatal care. The obstetric history and complications in pregnancy, such as diabetes and arterial hypertension, were referred by the woman during the interview in the maternity ward after giving birth with the question: “Did you have any of these health issues during pregnancy?” High blood pressure or eclampsia ; gestational diabetes .Associação Brasileira de Empresas de Pesquisa (ABEP – Brazilian Association of Research Companies) and was based on the family property and householder’s educational level, which composed the final score that defines socioeconomic groups: A (highest), B, C, D and E (lowest).The socioeconomic classification followed the criterion adopted by 2), adequate weight , overweight  and obesity .The datum about pregestational weight was obtained from the pregnant medical record until the thirteenth gestational or, if unavailable, it was self-reported by the patient. This weight was used to calculate body mass index (BMI) before pregnancy, allowing to classify the nutritional status of pregnant women in four categories: underweight  and the Kaiser-Meyer-Olkin (KMO) measure of sampling adequacy.The factor extraction was performed by principal component analysis (PCA), orthogonally transformed, with Varimax rotation to obtain a structure with independent factors, which helped in the interpretation.The definition of factors to be retained was based on scree plot , on the percentage of variance explained by factors and on the knowledge of the researchers (considerations on interpretability and simplicity of patterns). Then a new factor analysis was conducted with the establishment of the number of factors to be extracted.We kept in the factors (patterns) the items with factor loading higher than 0.30 and considered acceptable minimum commonalities of 0.25.The association between dietary patterns and birth weight was assessed by the multivariate linear regression model. Initially, we conducted the bivariate linear regression analysis between all exposure variables and birth weight, in addition to bivariate linear regression analysis between all covariates of the study and dietary patterns to detect possible confounding factors. A separate analysis was conducted for each dietary pattern. All covariates with p < 0.20 in both analyses were considered feasible elements for the final model. The final model was also mutually adjusted by other dietary patterns, given that, in this kind of analysis, individuals participate in more than one pattern, which are not correlated due to the rotation method used.The study was approved by the Research Ethics Committee of Escola Nacional de Saúde Pública (ENSP/Fiocruz – CAAE 0156.0.031.000-06), in accordance with the ethical principles stipulated by Resolution 196/96 of the National Health Council .The statistical analyses were carried out with the software Statistical Package for Social Sciences (SPSS) for Windows, version 16.0.The average age of the women interviewed was 24.7 years, and the average years of study was less than eight. Most women had no paid job (59.7%) and were in the economic classes B or C (66.4%). Most of them already had more than one child and 12.8% had prior history of newborn infants with low birth weight, prematurity or perinatal death .Considering the adequacy of number of prenatal visits for gestational age (Kotelchuck index),It was observed that 28.8% of women started pregnancy under an inadequate nutritional status and, of these, 20.0% were overweight. The average of weight gain in pregnancy was 13.3 kg, but less than 1/3 of women had appropriate weight gain, and 37.5% had excessive gain. There was a predominance of vaginal birth (55.7%) and the average birth weight of newborns was 3,253 g .Initially, we identified seven factors with eigenvalues higher than 1.0, which explained the food consumption variance of 51.3% (data not presented in the tables). Based on the scree plot, eigenvalues and considering interpretability of patterns, four factors should be retained, which, altogether, explained 36.4% of the consumption variability .farofa/grits, and pork/sausages/egg, which accounts for 6.9% of the variance; and (4) snack pattern , which explains 5.7% of the variance (The four patterns of consumption were named and composed as follows: (1) prudent pattern , which explained 14.9% of the consumption; (2) traditional pattern , which explained 8.8% of the variation in consumption; (3) Western pattern  for having very low commonality and not adjusting in any of the patterns established.In bivariate analysis, considering the statistical significance lower than 20.0%, the prudent pattern was associated positively with economic class B or C, paid work, age, education level, more than adequate prenatal and excessive weight gain in pregnancy, and was inversely associated with smoking in pregnancy. The pregnant women classified in traditional or Western pattern had some common features, such as: higher parity, smoking in pregnancy and lower pregestational obesity. The pregnant women classified in snack pattern were significantly younger, with less overweight and pregestational obesity, and more inadequate prenatal .In relation to birth weight, we observed positive association for the following variables: social class B or C, maternal age, education level, pregestational overweight or obesity, excessive gestational weighted gain, and cesarean delivery. In contrast, not living with a partner, being primipara, starting prenatal care with low weight, having inadequate weight gain, receiving inadequate prenatal care, and smoking during pregnancy were negatively associated with birth weight .The variables that had association with significance level of 20.0% with birth weight and dietary patterns, and which were adjusted in the final model, in addition to other dietary patterns, were: economic class, age, education level of the mother, marital status, parity, pregestational nutritional status, adequacy of prenatal care, perinatal death history, low birth weight or prematurity, smoking during pregnancy and delivery type  and 4.In the multivariate analysis, we observed positive association between snack pattern and birth weight, after adjustment according to maternal age, education level of the mother, marital status, social class, parity, pregestational BMI, adequacy of prenatal care, previous history of low birth weight/prematurity, smoking during pregnancy, newborn sex and type of delivery (data not shown). This association was observed after the inclusion of maternal age in the model, and not in the crude analysis, which showed the presence of negative confusion. It was observed that the distribution of the average factor score of the snack pattern also differed according to age group (0.44 in women between 10 and 19 years old and -0.13 in women 20 or more years of age) (data not presented in tables). These findings explain the attenuation of the effect observed in the crude analysis. Thus, the final model was stratified by maternal age .The multivariate linear regression analysis adjusted for confounding factors showed a positive association between the snack pattern and birth weight among pregnant adolescents .,The results of this study show that, in general, pregnant women who had prenatal care at the selected health units (SUS) of Queimados and Petropolis were young and from low socioeconomic class, features similar to other studies with pregnant women and recent mothers who used the services of SUS basic unities.Regarding anthropometric assessment of these women, although 64.9% of them were in an adequate nutritional status at the beginning of pregnancy, the prevalence of overweight was high (26.9%). This result is similar to that found in the study of Nucci et al,The average weight gain in pregnancy (13.3 kg) is similar to that found by Lacerda et alThe information on birth weight show that, in this study, the average weight  was a little bit higher  to the one found in another location.The factor analysis allowed identifying four dietary patterns that have food in common with dietary patterns identified by other researches.,,The prudent pattern, also called “healthy” in other studies with pregnant women, has fruit, fresh-fruit juice, vegetables, fish, and poultry.,The traditional pattern – beans, rice, vegetables, bread and butter/margarine – represents foods that are part of the Country’s eating habits and are similar to the traditional pattern found in studies that used the same analysis procedures for the extraction of dietary patterns.farofa/grits, soft drinks/cool drinks). This pattern also includes source of proteins such as pork, egg, sausages – the latter with low nutritional quality, as it contains large amounts of saturated fat, cholesterol and sodium. Fast foods (pizza/hamburger/deep fried pastries) are also present in this pattern and have low nutritional value and high energy density.The Western pattern is composed by foods with high-energy density, low nutritional value (low amount or free from micronutrients) and low financial cost, in addition to containing foods with a high proportion of carbohydrates  is also composed of foods of low nutritional value and with high-energy density. In the study conducted by Northstone et al,,,,,,,,,,The variables selected as confusion factors in the final statistical model have a theoretical rationale. Birth weight is an important health indicator and indirectly reflects the living conditions of populations.The analysis of the relationship between food consumption and birth weight showed that, for pregnant adolescents, the greater the adherence to the snack pattern, the greater the baby’s birth weight. This association was probably observed only among younger pregnant women because they are the biggest consumers of this pattern, since they presented mean positive factor score, whereas this mean was negative among women with 20 years of age or over.The snack pattern consists of foods with high concentrations of simple carbohydrates, lipids and low amounts of protein and micronutrients. This combination of nutrients gives these foods high-energy density, favoring gestational weight gain.A diet with a lot of energy is associated with higher gestational weight gainUusitalo et alSome methodological limitations of this study should be mentioned. Among them, the small number of foods listed in the FFQ and the lack of standardized portions for all items. In addition, the FFQ used was not tested regarding accuracy of food estimation, but only in relation to nutrients. Despite these limitations, the results obtained by the questionnaire are consistent with other studies, as the one performed by Barros et al,Another important factor related to subjectivity, which involves factor analysis, is the specificity of results obtained with this technique for the population investigated, making difficult the comparison between studies. Moreover, although most women included in our study live in poverty, the factors related to socioeconomic characteristics and lifestyle had relation to eating habits.There is consensus in the literature that the evaluation of maternal food consumption during pregnancy is important, and studies that address this subject are still scarce. We have not found studies conducted in Brazil on the effect of maternal dietary pattern on the baby’s birth weight. Thus, this study sought to contribute to determine dietary patterns during pregnancy. The epidemiological importance of these results, based on the cohort study in two Brazilian cities, lies in the provision of subsidies for the rationality of most appropriate nutritional intervention strategies for pregnant women. ,O peso ao nascer é importante indicador da sobrevivência infantil e reflete o risco de morte e agravos à saúde durante o primeiro ano de vida.Historicamente, a maior parte dos estudos epidemiológicos tinha como foco principal avaliar a associação entre consumo de nutrientes e desenvolvimento de doenças.Abordar o consumo alimentar através da identificação de padrões alimentares vem sendo descrito como método que mais se aproxima do complexo ato de se alimentar,,Entretanto, poucos estudos têm avaliado o padrão de consumo alimentar entre as gestantes, particularmente suas repercussões sobre o feto.Este estudo objetivou analisar se padrões de consumo alimentar durante o terceiro trimestre gestacional estão associados ao peso ao nascer.Este estudo faz parte do projeto “Capital Social e Fatores Psicossociais associados à Prematuridade e ao Baixo Peso ao Nascer”, realizado nos municípios de Petrópolis e Queimados, RJ, entre dezembro de 2007 e agosto de 2008.Foram convidadas a participar da coorte todas as gestantes com até 22 semanas de idade gestacional, atendidas nos serviços de pré-natal de 11 unidades de saúde da rede municipal do Sistema Único de Saúde (SUS), sendo oito em Queimados e três em Petrópolis, RJ, as quais detinham 90,0% da cobertura do cuidado pré-natal do SUS.Para cálculo do tamanho amostral da coorte, considerou-se prevalência de 10,0% de nascimentos prematuros e com baixo peso, nível de significância de 5% e poder de 90,0%, para detectar diferenças de pelo menos 5,0%.Devido a nascimentos prematuros (n = 167), perda de seguimento (n = 104), recusas (n = 71), abortos (n = 62), falta de informação do peso ao nascer (n = 31) e presença de gestação gemelar (n = 17), a amostra do presente estudo foi composta por 1.298 mulheres.stepwise que explicasse 95,0% da variância para os seguintes nutrientes: energia, carboidrato, lipídeos, ácidos graxos saturados, monoinsaturados e polinsaturados, colesterol, cálcio e vitamina C.O consumo alimentar foi avaliado por meio de questionário de frequência de consumo alimentar (QFA) semiquantitativo, referente ao último trimestre gestacional, composto por 29 itens alimentares e obtido por simplificação do QFA de 80 itens, validado por Sichieri e Everhart.A informação sobre o peso ao nascer foi extraída dos prontuários médicos. Quando não estava disponível, foram utilizados os dados da caderneta da criança ou da declaração de nascido vivo.Foram avaliadas as seguintes variáveis de exposição: (i) sociodemográficas: idade das gestantes em anos, estado marital , cor de pele autorreferida , escolaridade em anos de estudo, trabalho fora de casa , classe econômica ; (ii) tabagismo ; (iii) doenças crônicas autorreferidas: hipertensão arterial , diabetes mellitus ; (iv) antecedentes obstétricos: paridade , história anterior de óbito perinatal, baixo peso ao nascer ou prematuridade; (v) estado nutricional materno  e (vi) adequação do pré-natal. A história obstétrica e intercorrências na gestação, como diabetes e hipertensão arterial, foram referidas pela mulher na entrevista na maternidade após o parto, por meio da pergunta: “Você teve algum desses problemas de saúde na gravidez?” Pressão alta ou eclâmpsia ; Diabetes gestacional .A classificação socioeconômica seguiu critério adotado pela Associação Brasileira de Empresas de Pesquisa, baseado nos bens da família e no grau de instrução do seu respectivo chefe, constituindo-se escore final que define os grupos socioeconômicos A , B, C, D e E (o mais baixo).2), sobrepeso  e obesidade .26 A partir dessas informações, foram determinadas as faixas de adequação de peso para cada gestante, equivalente a ganho ponderal gestacional total de: 12,5 a 18 kg para mulheres com baixo peso pré-gestacional; 11,5 a 16 kg para mulheres eutróficas; 7 a 9 kg para mulheres com sobrepeso; e 7 kg para mulheres obesas.O dado de peso pré-gestacional foi obtido do cartão da gestante até a 13ª semana gestacional ou, quando indisponível, considerou-se o peso pré-gestacional autorrelatado. Esse peso foi utilizado para calcular o índice de massa corporal (IMC) prévio à gestação, permitindo classificar o estado nutricional da gestante em quatro categorias: baixo peso  e a medida de adequação da amostra de Kaiser-Meyer-Olkin (KMO).A extração dos fatores foi feita pela análise de componentes principais (ACP), ortogonalmente transformados, utilizando-se a rotação Varimax para obtenção de uma estrutura com independência dos fatores, facilitando a interpretação.scree plot , no percentual da variância explicada pelos fatores e no conhecimento dos pesquisadores (considerações sobre interpretabilidade e simplicidade dos padrões). Realizou-se então nova análise fatorial fixando-se o número de fatores a serem extraídos.A definição dos fatores a serem retidos baseou-se no Foram mantidos, nos fatores (padrões), os itens com carga fatorial superior a 0,30 e consideradas aceitáveis comunalidades mínimas de 0,25.A associação entre padrões alimentares e peso ao nascer foi avaliada por modelo de regressão linear multivariado. Inicialmente, foi feita a análise de regressão linear bivariada entre todas as variáveis de exposição e o peso ao nascer, além de análise de regressão linear bivariada entre todas as covariáveis do estudo e os padrões alimentares com o intuito de detectar os possíveis fatores de confusão. Foi realizada análise distinta para cada padrão alimentar. Todas as covariáveis com p < 0,20 em ambas as análises foram consideradas potenciais candidatas para comporem o modelo final. O modelo final também foi mutuamente ajustado pelos demais padrões alimentares, dado que, nesse tipo de análise, os indivíduos participam de mais de um padrão e estes são não correlacionados, devido ao método de rotação empregado.O estudo foi aprovado pelo Comitê de Ética em Pesquisa da Escola Nacional de Saúde Pública (ENSP/Fiocruz – CAAE 0156.0.031.000-06), estando de acordo com os princípios éticos contidos na Resolução 196/96, do Conselho Nacional de Saúde .Statistical Package for Social Sciences (SPSS) forWindows, versão 16.0.As análises estatísticas foram realizadas no programa estatístico A idade média das mulheres entrevistadas foi 24,7 anos, a média de anos de estudo foi inferior a oito. A maioria das mulheres estava sem trabalho remunerado , e pertencia às classes econômicas B ou C . A maioria já possuía mais de um filho e 12,8% apresentava história anterior de recém-nascido com baixo peso ao nascer, prematuridade ou óbito perinatal .Considerando-se a adequação do número de consultas de pré-natal para a idade gestacional (índice de Kotelchuck),Observou-se que 28,8% das mulheres iniciaram a gestação com estado nutricional inadequado e, destas, 20,0% apresentavam sobrepeso. A média de ganho de peso na gestação foi de 13,3 kg, porém menos de 1/3 das mulheres apresentou ganho de peso considerado adequado e 37,5% apresentou ganho excessivo. Houve predomínio do parto vaginal  e o peso médio ao nascer do recém-nascido foi 3.253 g .scree plot, nos autovalores e considerando a interpretabilidade dos padrões, deveriam ser retidos quatro fatores que, juntos, explicavam 36,4% da variabilidade de consumo . Com base no  consumo .Os quatro padrões de consumo foram denominados e compostos da seguinte forma: (1) padrão prudente, composto por leite, iogurte, queijo, frutas e suco natural, biscoito sem recheio e carne de frango/boi/peixe/fígado, que explicava 14,9% do consumo; (2) padrão tradicional, composto por feijão, arroz, vegetais, pães, manteiga/margarina e açúcar, que respondeu por 8,8% da variação do consumo; (3) padrão ocidental, composto por pizza/hambúrguer/pastel, batata/aipim/inhame, refrigerante/refresco, macarrão, farinha/farofa/angu, carne de porco/salsicha/linguiça/ovo, responsável por 6,9% da explicação da variância; e (4) padrão lanche, composto por biscoito recheado, biscoitos tipo salgadinho, chocolate e achocolatado, explicando 5,7% da variância .Todos os grupos alimentares se associaram a algum dos quatro padrões identificados e apenas um item alimentar foi excluído da análise (café/chá preto ou chá mate) por apresentar comunalidade muito baixa, não se enquadrando em nenhum dos padrões definidos.Na análise bivariada, considerando-se a significância estatística menor que 20,0%, o padrão prudente associou-se positivamente com classe econômica B ou C, trabalho remunerado, idade, escolaridade, pré-natal mais que adequado e excesso de ganho de peso na gestação, e associou-se inversamente com o fumo na gestação. As gestantes classificadas no padrão tradicional ou ocidental apresentaram algumas características comuns, como: maior paridade, fumo na gestação e menor obesidade pré-gestacional. Gestantes classificadas no padrão alimentar lanche eram significativamente mais jovens, com menos sobrepeso e obesidade pré-gestacional e mais pré-natal inadequado .Em relação ao peso ao nascer, mostraram associação positiva as variáveis classe social B ou C, idade materna, escolaridade, sobrepeso ou obesidade pré-gestacional, ganho ponderal excessivo na gestação e parto cesáreo. Contrariamente, não ter companheiro, ser primípara, iniciar o pré-natal com baixo peso, apresentar ganho de peso insuficiente, fazer pré-natal inadequado e fumar durante a gestação associaram-se negativamente com o peso ao nascer .As variáveis que apresentaram associação com significância de 20,0% tanto com o peso ao nascer quanto com os padrões alimentares e que entraram no ajuste do modelo final, além dos demais padrões alimentares, foram: classe econômica, idade, escolaridade materna, situação conjugal, paridade, estado nutricional pré-gestacional, adequação do pré-natal, histórico de óbito perinatal, baixo peso ao nascer ou prematuridade, fumo durante a gestação e tipo de parto  e 4.Na análise multivariada, observou-se associação positiva entre consumo do padrão lanche e peso ao nascer, após ajuste por idade materna, escolaridade materna, situação conjugal, classe social, paridade, IMC pré-gestacional, adequação do pré-natal, história anterior de baixo peso/prematuridade, fumo durante a gestação, sexo do bebê e tipo de parto (dados não apresentados). Essa associação foi observada após a inclusão da idade materna no modelo, e não na análise bruta, o que mostra a presença de confusão negativa. Observou-se ainda que a distribuição da média do escore fatorial do padrão lanche também diferiu segundo faixa etária  (dados não apresentados em tabela). Estes achados explicam a atenuação do efeito observada na análise bruta. Assim, o modelo final foi estratificado por idade materna .A análise de regressão linear multivariada ajustada para os fatores de confundimento mostrou associação positiva entre o padrão alimentar lanche e o peso ao nascer entre as gestantes adolescentes .,Os resultados deste estudo mostram que, de forma geral, as gestantes atendidas nos serviços de pré-natal das unidades selecionadas dos municípios de Queimados e Petrópolis do Sistema Único de Saúde (SUS) eram jovens e de baixo nível socioeconômico, características semelhantes a de outros estudos realizados com gestantes e puérperas atendidas em unidades básicas do SUS.Com relação à avaliação antropométrica das mulheres, apesar de 64,9% delas terem iniciado a gestação com estado nutricional adequado, a prevalência de excesso de peso foi alta . Esse resultado é semelhante ao encontrado no estudo de Nucci et al,A média de ganho de peso gestacional  assemelha-se à encontrada por Lacerda et alAs informações sobre o peso ao nascer mostram que, neste estudo, o peso médio (3.253 g) foi pouco superior (3.142 g) ao encontrado em outra localidade brasileira.A análise fatorial permitiu identificar quatro padrões alimentares, que possuem alimentos em comum com padrões alimentares identificados em outras pesquisas.,,O padrão prudente, também designado em outros estudos com gestantes como “saudável”, caracteriza-se pela presença de frutas, suco natural, vegetais, peixes e aves.,O padrão tradicional, contendo feijão, arroz, vegetais, pães e manteiga/margarina, representa os alimentos que fazem parte do hábito alimentar brasileiro e se assemelha ao padrão tradicional, encontrado em estudos que utilizaram os mesmos procedimentos de análise para extração de padrões alimentares.fast foods (pizza/hambúrguer/pastel) também estão presentes nesse padrão e possuem baixo valor nutricional e elevada densidade energética.O padrão ocidental é composto por alimentos com elevada densidade energética, baixo valor nutritivo (baixa quantidade ou isentos de micronutrientes) e de baixo custo financeiro, além de conter alimentos com elevada proporção de carboidrato . Esse padrão também inclui alimentos fonte de proteínas, como carne de porco, ovo, linguiça e salsicha, sendo os dois últimos de baixa qualidade nutricional, pois contêm grande quantidade de gordura saturada, colesterol e sódio. Os alimentos O padrão lanche  também é composto por alimentos de baixo valor nutritivo e alta densidade energética. No estudo de Northstone et al,,,,,,,,,,As variáveis selecionadas como fatores de confusão no modelo estatístico final apresentam um racional teórico. O peso ao nascer é um importante indicador de saúde, refletindo indiretamente as condições de vida das populações.A análise da relação entre padrões de consumo alimentar e peso ao nascer mostrou que, para as gestantes adolescentes, quanto maior a adesão ao padrão lanche, maior o peso ao nascer do bebê. Possivelmente, esta associação foi observada apenas entre as gestantes mais jovens por serem estas as maiores consumidoras deste padrão, uma vez que apresentaram escore fatorial médio positivo, enquanto que esta média foi negativa dentre as mulheres com 20 ou mais anos de idade.O padrão alimentar lanche é composto por alimentos com altas concentrações de carboidrato simples, lipídeos e baixas quantidades de proteína e micronutrientes. Essa combinação de nutrientes confere a esses alimentos uma elevada densidade energética, favorecendo o ganho de peso gestacional.Uma dieta com grande quantidade de energia está associada a um maior ganho de peso gestacionalfast food e padrão álcool e gordura. Os autores concluíram que as mulheres que pertenciam ao maior quartil de consumo do padrão fast food ganhavam em média 1,3 kg a mais do que as que pertenciam ao menor quartil deste padrão. Por outro lado, mulheres que pertenciam ao quartil de consumo mais elevado do padrão álcool e gordura ganhavam em média 0,7 kg a menos do que as que pertenciam ao menor quartil de consumo deste padrão.Uusitalo et alAlgumas limitações metodológicas deste estudo devem ser mencionadas. Dentre elas, o pequeno número de alimentos do QFA e a falta de porções padronizadas para todos os alimentos. Além disso, o QFA utilizado não foi testado quanto à acurácia na estimativa de alimentos, mas apenas de nutrientes. A despeito dessas limitações, os resultados obtidos pelo questionário são coerentes com o de outros estudos, como o realizado por Barros et al,Outro fator importante que se relaciona à subjetividade, envolvendo a análise fatorial, é a especificidade dos resultados obtidos através desta técnica para a população investigada, dificultando a comparação entre os estudos. Além disso, apesar de as mulheres incluídas neste estudo viverem, majoritariamente, em situação de pobreza, os fatores referentes às características socioeconômicas e de estilo de vida apresentaram relação com hábitos alimentares.Existe consenso na literatura de que a avaliação do consumo alimentar durante a gestação é importante e os estudos que abordam este tema ainda são escassos. Não foram encontrados estudos nacionais que avaliassem o efeito da alimentação materna sobre o peso ao nascer. Assim, esta pesquisa procurou contribuir com a determinação de padrões alimentares durante a gestação. A importância epidemiológica destes resultados, com base no estudo de coorte em dois municípios brasileiros, reside no fornecimento de subsídios para a racionalidade de estratégias nutricionais de intervenção mais apropriadas para gestantes.


Dc for the half-metallicity being an issue in recent works on ZGNRs. A properly chosen direction of the electric field alone has been predicted to significantly reduce Dc in the hydrogenated CNTs, which in this work turned out to be the case in narrow bilayer ZGNRs (biZGNRs). Here, our simple model based on the electrostatic potential difference between the edges predicts that for wide biZGNRs of width greater than ~2.0 nm (10 zigzag carbon chains), only one layer of the biZGNRs becomes half-metallic leaving the other layer insulating as confirmed by our density functional theory (DFT) calculations. The electric field-induced switching of the spin-polarized current path is believed to open a new route to graphene-based spintronics applications.Half-metallicity recently predicted in the zigzag-edge graphene nanoribbons (ZGNRs) and the hydrogenated carbon nanotubes (CNTs) enables fully spin-polarized electric currents, providing a basis for carbon-based spintronics. In both carbon systems, the half-metallicity arises from the edge-localized electron states under an electric field, lowering the critical electric field  While U(LB)-U(RA) = E3-E2 is smaller than U(LB)-U(RB) = E3-E1 in the absence of an electric field, the electric field-induced energy level shift leading to reduction of the band gap in U(LB)-U(RB) may be greater than that in U(LB)-U(RA). From the two gaps, the electric field required for the band gap closure can be obtained as< E4 see . The eneDc1 and Dc2 correspond to the band gap closure in a layer and between layers, respectively, the smaller of the two being the critical electric field Dc for a band gap closure in the biZGNRs.Dc = Dc2, half-metallicity occurs between the two layers. On the other hand, when Dc = Dc1, only one of the layers becomes half-metallic leaving the other insulating, which would happen in wide enough biZGNRs. In this case, inversion of the electric field direction would lead to a band gap closure in the opposite spin channel, giving rise to a switching between the half-metallic and the insulating layers. Thus, our model predicts a layer-selective half-metallicity in wide enough biZGNRs and allows one to switch the path of the spin current by switching the electric field direction.When x-axis. Only the PDOS of the edge carbon atoms is shown in n-biZGNRs with n ≥ 10.The layer-selectivity predicted by the model was confirmed by the calculations of the projected density of states (PDOS) for the edge carbon atoms in biZGNRs. x-axis, the spatial separation between the two spin channels leads to energy level shifts of opposite signs for them giving rise to half-metallicity (Dc(θ) were obtained from the band edges of the valence and conduction bands in n-biZGNRs as a function of n (θM of minimum Dc(θ) is nonzero for n < 10, decreasing with increasing n and finally becoming zero at n = 10, for which the layer-selective half-metallicity sets in. Dc is described well by our simple model introduced above. The critical electric field Dc(θM) for half-metallicity is shown to be inversely proportional to the nanoribbon width  and the related quantities were calculated with k points of 1 × 1 × 1000 mesh. The atomic coordinates were optimized by using conjugated gradients method with a maximum force tolerance of 0.01 eV/Å in the absence of an electric field. The lattice parameter was set to a = 2.45778 Å. To simulate the external electric field, a periodic sawtooth potential was used. The supercell has 1.5-nm vacuum spacing in the x-direction and 1-nm vacuum spacing in the y-direction to avoid any intercell interactions.A SIESTA version 3.2 package was employed for the DFT calculation19In DFT codes using plane wave base sets, graphene layers have been reported not to bind with a standard GGA functional, the repulsive force being overestimated2224K.W.L. initiated the study and contributed to the interpretation of the data. G.W.J. performed DFT calculations and analyzed data. C.E.L. supervised the project. G.W.J., K.W.L., and C.E.L. wrote the manuscript.How to cite this article: Jeon, G. W. et al. Layer-selective half-metallicity in bilayer graphene nanoribbons. Sci. Rep.5, 9825; doi: 10.1038/srep09825 (2015).


Consequently, ambient concentrations of nitrogen dioxide  in NO2 concentration associated with a 13.78 g  reduction in birth weight. This association was maintained after adjusting for other pollutants, including carbon monoxide (CO), sulfur dioxide (SO2), and PM10. No relationship was found between the concentration of PM10 and low birth weight among full-term births. Neither PM10 nor NO2 concentrations predicted the risk of premature birth.Among full-term births, maternal exposure to NOExposure to ambient air pollution during certain periods of pregnancy may decrease birth weight, but the effect size is small. Adverse birth outcomes, including preterm birth and low birth weight, are an important global public health issue. Fifteen million babies are born premature (less than 37 weeks) worldwide each year . Low birExperimental studies on laboratory animals found changes in reproductive function after the animals were exposed to air pollution –6. In hu10 and NO2, which are primarily generated by motor vehicles in these areas [10 in Beijing was reduced from 130 ug/m3 in July-September 2007 to approximately 70 ug/m3 during the Olympic Games Traffic Control period in 2008 , carbon monoxide (CO), nitrogen dioxide (NO2), and particulate matter 10 micrometers or less (PM10). At each site, a tapered element oscillating microbalance (TEOM)  measured the PM10 concentrations, a pulsed fluorescence gas analyzer  recorded SO2 concentrations, a chemiluminescence technology device  measured NO2 concentrations, and a gas filter correlation analyzer  recorded CO concentrations. All measurements were recorded hourly. They were averaged to daily levels at all of the sites and then combined and averaged to obtain citywide daily levels. The arithmetic mean of the citywide daily levels was then calculated to obtain citywide monthly level.We used data on ambient air pollutants from 28 air quality monitoring sites located in the metropolitan area of Beijing, which are operated by the Beijing Municipal Environmental Monitoring Center, an institutional agency affiliated with the Beijing Municipal Environmental Protection Bureau. The Chinese government monitors four air pollutants considered hazardous to human health: sulphur dioxide (SOHuji) status, and fertility history of women were collected at admission. Birth weight was measured within 24 h after delivery. Gestational age (GA) was determined from the date of the mother’s last menstrual period confirmed by a sonographic examination prior to 20 weeks of gestation. The quality of the data has been discussed elsewhere and is considered high-standard. [n = 50,874) delivered at HMCHH between January 1, 2007, and December 31, 2010, as well as births delivered in late 2006, when the hospital began collecting information on all of the variables included in this study. This relatively short time frame helps to mitigate potential confounding bias associated with long-term changes, such as improvements in prenatal health care and nutritional transitions. We used the standard definitions of preterm birth, which is a baby born at less than 37 weeks gestational age, and trimester divisions of 0–13 weeks, 14–26 weeks, and 27 weeks to birth. We assigned each newborn to a corresponding daily exposure for each pollutant, starting from the date of conception until the date of birth, which was then averaged for each trimester of gestation.The data of maternal and child health were obtained from the Beijing Haidian Maternal & Child Health Hospital (HMCHH), which provides maternal and child health care to Beijing residents, primarily those in the Haidian district. In addition, the HMCHH performs medical exams on approximately 10,000 newborns annually. Data on birth date, education, household registration  of the family , maternal age at delivery, and parity . Because seasonality of conception is associated with both socio-economic factors and birth outcomes [2 and CO concentrations in the first, second, and third trimester of the pregnancy. In addition, to examine the crude effect of each individual pollutant, we produced a series of single-pollutant models for PM10 and NO2. Because missing data was rare, we excluded cases with missing values from the regression analysis. All analyses were performed with the software package SAS, version 8.2 . This study was approved by the Institutional Review Board (IRB) at George Washington University.outcomes , we cont2, NO2, CO, PM10) in Beijing from 2006 to 2010. The concentrations of SO2, NO2, CO, and PM10 were positively correlated with each other (0.45 < r < 0.87). The concentrations of all pollutants were far greater than the World Health Organization (WHO) air quality standard. For example, the annual mean of PM10 in Beijing during the period 2006–2010 is 134.72 ug/m3, about six times higher than recommended by the WHO (20 ug/m3) [Table 0 ug/m3) .Table 1Chuji) was registered as “Beijing Urban (Cheng Qu)”, while 27.2 % of the infants were born to parents registered as “urban huji of other province”. The average maternal age at delivery was 29.2 years with a standard deviation of 3.6. As a result of the strictly enforced family planning policy in urban China, the majority (87.9 %) of the newborns were firstborns.Results from descriptive analysis show that 6.3 % of the newborns delivered at HMCHH were born prematurely (GA less than 37 complete weeks). 54.7 % of the infants were born to parents whose household registration (n = 1784) and 2477.2 g for females (n = 1387), was less than the mean birth weight of the term sample 3453.7 g for males  and 3331.4 g for females .Table 2 nor PM10 predicted the risk of preterm delivery.Table 2 in the third trimester predicted lower birth weights, with each 10-unit increment (per 10 ug/m3) in NO2 concentration associated with a 13.78 g  reduction in birth weight. Results from the multi-pollutant model suggest that this association is maintained after adjusting for other pollutants including CO, SO2, and PM10, and that each ten-unit increment (per 10 ug/m3) in NO2 concentration is associated with a 14.78 g  reduction in birth weight. These effects are statistically significant but considered small as the effect sizes are less than 0.1 [10 and birth weight, with or without adjustment for the concentration of other pollutants.Table than 0.1 . No rela2 in the third trimester and birth weight. Specifically, maternal exposure to NO2 in the third trimester predicted a reduced birth weight among full-term newborns, with or without controlling for other pollutants.The 2008 Beijing Olympic Games provided a natural experiment setting in which the strict environmental regulations implemented by the Chinese government resulted in a substantial but temporary improvement in air quality. This enabled us to examine the effects of ambient air pollution exposure on adverse birth outcomes. We did not find any correlations between maternal exposure to ambient pollutants and preterm births. However, we observed small-magnitude associations between maternal exposure to NO10 [Several studies have examined fetal growth and exposure to ambient air pollution by trimester, and the findings have been widely varied, making conclusions difficult to draw . Some st10 –21. Howe10 , while a10 . The evi10 –26, whil10 , 26. FurAlthough not yet validated, several potential mechanisms may explain the significant, albeit small, relationship between ambient air pollution exposure during pregnancy and low birth weight.  Ambient The findings from this study should be interpreted with caution. First, this study extrapolated information from city-wide measurements of ambient air pollution, and we were unable to draw conclusions based on exposures to air pollutants at the individual level. Certain uncontrolled factors, such as occupation and mobility, may have affected each individual’s level of exposure to ambient air pollutants. Second, our natural experiment design may have been subject to other changes that simultaneously contributed to the improvement of air quality during the Olympic Games. For example, exposure to secondhand smoking during pregnancy, a well-known risk factor of preterm birth and low birth weight of newborns, may have been mitigated during the games when public smoking regulations were likely implemented, decreasing the risk of adverse birth outcomes. Future studies may benefit from a prospective cohort research design that allows researchers to use biomarkers of exposure at an individual level and the collection of detailed information on characteristics of study subjects, including behaviors, when feasible .Nevertheless, our study, based on a natural experiment approach, provided further evidence that ambient air pollution may be associated with reduced birth weights, albeit the effect sizes are small, which is consistent with previous studies based on other designs , 7. Such