Rx rate . The polypharmacology profiles of SGLT2i were data‐mined (ChEMBL) for the first time. The ADR reports (n = 3629) and prescribing numbers  for each SGLT2i in the United Kingdom (from launch date to the beginning December 2019) were determined. Empagliflozin possesses the most selective SGLT2/SGLT1 inhibition profile at ~2500‐fold, ~10‐fold more selective than cangliflozin (~260‐fold). Canagliflozin was found to also inhibit CYP at clinically achievable concentrations. We find that for overall ADR rates, empagliflozin versus dapagliflozin and empagliflozin versus canagliflozin are statistically significant , while dapagliflozin versus canagliflozin is not. In terms of overall ADRs, there is a greater relative rate for canagliflozin > dapagliflozin > empagliflozin. For fatalities, there is a greater relative rate for dapagliflozin > canagliflozin > empagliflozin. An organ classification that resulted in a statistically significant difference between SGLT2i was suspected infection/infestation ADRs between empagliflozin and dapagliflozin. Our findings at this stage of SGLT2i usage in the United Kingdom suggest that empagliflozin, the most selective SGLT2i, had the lowest suspected ADR incident rate (relative to prescribing) and in all reported classes of ADRs identified including infections, amputations, and DKA.Sodium glucose co‐transporter 2 inhibitors (SGLT2i) are a promising second‐line treatment strategy for type 2 diabetes mellitus (T2DM) with a developing landscape of both beneficial cardio‐ and nephroprotective properties and emerging adverse drug reactions (ADRs) including diabetic ketoacidosis (DKA), genetic mycotic infections, and amputations among others. A national register study  was used to quantify the SGLT2i's suspected ADRs relative to their  At this stage of prescribing in the UK, the lowest percentage of suspected adverse drug reactions (ADRs) and fatalities was found with Empagliflozin ADRsadverse drug reactionsAKIacute kidney injuryCKDchronic kidney diseaseDKAdiabetic ketoacidosisSGLT2iSodium glucose co‐transporter 2 inhibitorsT2DMtype 2 diabetes mellitus1Sodium glucose co‐transporter 2 inhibitors (SGLT2i) are a relatively new class of antidiabetic medication for type 2 diabetes.dapagliflozin (2012), canagliflozin (2013), empagliflozin (2014), and ertugliflozin (2019), respectively.In comparison to other antidiabetic medication,The inhibition of SGLT2 leads to the reduction in blood pressure, body weight,Adverse drug reactions (ADRs) are defined as harmful and unintended events in response to a drug related to any dose.Our continuing research interest in the intersection of medicinal chemistry22.1Physicochemical properties are intrinsic to each SGLT2i and have an impact on how they behave in the body including permeability, clearance, and absorption.pKa, Log10P, and Log10D values were datamined from ChEMBL using the search terms of each drug's name. Calculated properties were obtained using the ChemDraw 19.0 software based on the chemical structure of each drug.The Electronic Medicines CompendiumpKa ; log10P (where P is the partition coefficient = concentration of solute in octanol divided by the concentration of solute in water); log10D is the distribution constant of a drug between the aqueous and lipid phases at pH 7.4.Neutral or basic–acidic drug molecules are defined by the pIC50 was calculated using the median SGLT2 inhibitory IC50 of each drug; and lipophilic ligand efficiency (LLE) was calculated: LLE = pIC50–clog10P. Lipophilic ligand efficiency (LLE) measures how effective a drug binds to its target excluding nonspecific entropic factors. The LLE parameter is used to normalize potency relative to lipophilicity. A value of <5 is associated with increased toxicity.pKa); topological polar surface area (tPSA) <90 Å; logD7.4 1–3; and low affinity to efflux ABCB1 . The Cmax peak serum concentration of each SGLT2i was calculated from the FDA new drug application documentation.The following parameters were calculated; Non‐listed pharmacokinetic parameters on the ChEMBL database were collated through literature database searches of each drug name + pharmacokinetic OR PK search terms using Springer Link; NCBI; the electronic Medicines Compendium (eMC); and SciFinder (Caplus and Medline databases).2.2® database. Bioactivity was compared using IC50 values, with a minimum threshold set at 10 μM (to exclude weak interactions). IC50 is a quantitative measure that indicates how much of a substance (in this case a drug) is required to inhibit a biological component by 50%.Pharmacological bioactivity data were curated. The ChEMBL database (accessed on 01/11/2020) was used to gather quantitative measures between each SGLT2i and human proteins. SGLT2 activity data were also identified through cross‐checking literature using the Reaxys50 gives an overview of the relative affinity between SGLT2i across multiple targets and mitigates for reproducibility/reliability issue of selecting a single IC50.The mean ICAdditional polypharmacological inhibitory data were collected through Food Drug Administration (FDA) Secondary Pharmacology Data Review Documents.2.3http://www.guidetopharmacology.org and are permanently archived in the Concise Guide to PHARMACOLOGY 2019/20.Key protein targets and ligands in this article are hyperlinked to corresponding entries in 2.4https://yellowcard.mhra.gov.uk/iDAP/), from January 2013 to December 2019 for the studied SGLT2i. The ADR event data collection was terminated in January 2020 due to differences in reviewal dates between the Yellow Card Report Scheme and Open Prescribing.Reported suspected ADR data were extracted from the Medicines and Healthcare Regulatory Agency (MHRA) Yellow Card Interactive Drug Analysis Profile in the United Kingdom.The reporting system processed reports for all SGLT2i except for ertugliflozin. Ertugliflozin has only recently been approved for use in clinical practice (2019), and thus, no ADR data was available at the time of data collection. The Yellow Card Report scheme categorized ADRs by organ class, which was replicated in this study.n > 50) for each SGLT2i  or high levels of ADR within a particular organ class (above baseline). The ADR table included ADRs that are established and suspected ADRs that were reported  database collects data regarding prescription numbers for all prescribed drugs in England across all National Health Services (NHS) in primary care settings.The Open Prescribing (2.6χ2) test was performed on the standardized ADR/100,000xR data to determine statistically significant differences between the suspected ADRs and SGLT2i using Excel for Microsoft 365. A p‐value of <.05 was considered statistically significant.Chi‐squared  system. All SGLT2i are given orally and as single‐dose medication (Table Vd) is similar across all SGLT2i (73.8–85.5 L), the exception being dapagliflozin which has Vd of 118 L indicating its presence in tissues is higher than other class members.The physical properties of all SGLT2i are similar, all being s Figure . They haon Table . Volume 3.250 > 10 µM is considered a weak inhibitor and thus is clinically unachievable in most scenarios. SGLT2i Cmax range from 186 to 387 nM except for canagliflozin (2.8 µM).ICExhaustive data regarding the polypharmacology of the SGLT2i are available in Table 50 = 0.87 nM) and empagliflozin the weakest (IC50 = 3.1 nM).The primary pharmacological action of SGLT2i is the inhibition of SGLT2. Comparing SGLT2 inhibitory values, ertugliflozin is the most potent inhibitor (ICSGLT5 (IC50 = 820 nM) and canagliflozin's inhibition of SGLT6 (IC50 = 240 nM). SGLT2i are weak inhibitors of CYP450 isoforms, with exception of canagliflozin which inhibits CYP2D6 (IC50 = 1320 nM).The pharmacological activity includes inhibition of other SGLT isoforms . Inhibition of these transporters are weaker in comparison to the on‐target (>1000 nM) except for dapagliflozin's inhibition of SGLT1. Differences in selectivity between SGLT2is were noted.Selectivity values were approximations that compared inhibitory activity at SGLT2 versus Based on the physicochemical and polypharmacological data available, the following predictions can be made: empagliflozin is likely to emerge as the SGLT2i with the least number of serious ADRs due to high selectivity for SGLT2.3.3xR) as shown in parentheses  and canagliflozin had the lowest . To enable a fair comparison between SGLT2i with a wide range of prescribing numbers, standardized values were calculated , followed by dapagliflozin (78) then finally empagliflozin (44.07); this discrepancy resulted in a p < .05. A p < .05 was present for both the comparison between empagliflozin and dapagliflozin and the comparison between empagliflozin and canagliflozin but not dapagliflozin versus canagliflozin , followed by canagliflozin (0.562) and empagliflozin (0.213); further details are shown in Chart Dapagliflozin had the highest fatality rate per 100,000 The ADRs reported for GI system disorders were relatively high for all SGLT2i. Canagliflozin had the highest incident rate of 12.34, approximately two‐fold greater than empagliflozin (6.10). Dapagliflozin (11.07) had a similar ADR incident rate to canagliflozin, showing a differential between empagliflozin and the other SGLT2i.The incident rate for Fournier's gangrene, an ADR that has been reported to have an increased association with SGLT2i,Canagliflozin had the highest rate for amputations (1.17) when compared to empagliflozin and dapagliflozin where the incidence was observed to be similar, 0.53 and 0.57, respectively. Canagliflozin use was associated with toe (1.44) and foot amputations (0.11). However, empagliflozin and dapagliflozin use was associated with foot, toe, and leg amputations at a relatively low incidence. The ADR incident range for toe and leg amputations for both empagliflozin and dapagliflozin was 0.24–0.25 and 0.035–0.14, respectively.For all ADRs relative to the nervous system, dapagliflozin (7.59) and canagliflozin (7.78) had a two‐fold higher incidence of ADRs when compared to empagliflozin (3.41). This trend was repeated for neurological disorders, where empagliflozin had the lowest incidence (2.34) and both dapagliflozin and canagliflozin incidence was relatively similar (>5).For all ADRs relative metabolic disorders, empagliflozin had the lowest incidence (13.52) which was substantially different to both dapagliflozin and canagliflozin, 25.54 and 23.11, respectively. However, for DKA, the differential range between all three SGLT2i was considerably smaller as this ADR is prevalent with all of them (9.62–16.09). This corresponded to empagliflozin having the lowest and dapagliflozin having the highest. For euglycemic diabetic ketoacids, incidence was similar in both dapagliflozin and empagliflozin; however, in canagliflozin, the incidence was greater (2.67).4Cmax), indeed only canagliflozin is likely to be able to inhibit off‐targets SGLT1, SGLT6, and CYP isoforms potently in man.The aim of this research was to identify potential relationships between the pharmacological activity of SGLT2i with their suspected ADRs. Visual inspection of Table 4.1The polypharmacology of SGLT2i was predominantly of other SGLT transporters. In total, there are six SGLT transporters all coded by the SLC5A gene, but their functions and whereabouts in the body differ.SGLT3 which is not a monosaccharide transporter but instead a sensor in the brain.The roles of the remaining SGLT transporters (SGLT4‐6) are not fully elucidated to the best of our knowledge except for p < .05  which is responsible for numerous drugs transportation in the body and consequences of inhibition may lead to increase drug to drug interactions.In addition, dapagliflozin inhibited organic anionic transporter polymorph  give a complete listing of all the spontaneous suspected ADRs reported through the Yellow Card Scheme. While a valuable safety tool, there are several inherent limitations: underreporting of suspected ADRs is commonly encountered and may lead to the underestimation of any given reaction or drug even within the same class.Reporters are requested to report any suspected ADRs, and they do not have to demonstrate a clear causal link with the drug. These reported adverse reactions have not been proven to be related to the SGLT2i and should not be interpreted as a list of known side effects. Care needs to be taken with suspected fatal cases, where reporters may be more likely to err on the side of reporting due to the seriousness of the reaction. Other factors would need to be considered: co‐morbidities, co‐medications, genetics, and others. Therefore, some of these suspected ADRs may be due to third factor variables. Therefore, conclusions on the safety and risks of medicines cannot be made on the information obtained from the Drug Analysis Profiles alone. However, such data can be useful for hypothesis generation as in this study, standardized to prescribing rates, and supported by primary literature reports and case studies.The available data on the polypharmacology of SGLT2i is incomplete.5The results demonstrate a correlation between the selectivity of SGLT2i in relation to their respective suspected incidence of ADRs. As a class, SGLT2i are a safe and effective medication for the treatment of T2DM with relatively low incidence of ADRs and fatalities and may have potential for the treatment for other diseases (cardio‐ and nephroprotective properties).xR. Although a statistically significant difference between the SGLT2i could not be determined, empagliflozin consistently had the lowest ADR incidence out of all the studied SGLT2i.Empagliflozin emerged as the most prescribed SGLT2i in the United Kingdom, the most selective SGLT2i on the market, and has the lowest incidence rate of suspected ADRs across the SGLT2i class. For established ADRs, empagliflozin had both a relatively low incidence for all ADRs (44.07), infections (4.61), amputations (0.53), and diabetic ketoacidosis (9.62) per 100,000 ≅2200‐fold for SGLT2 over SGLT1).Due to the possible linkage between SGLT2i selectivity and incidence of suspected spontaneous ADRs, we would predict that ertugliflozin will have a similar ADR profile as empagliflozin (as data emerge), because of the drug's high selectivity (No conflict of interest to report.Supplementary MaterialClick here for additional data file.


Previous evidence indicates that birth season is associated with type 2 diabetes in adults. However, information on the association of birth with gestational diabetes mellitus (GDM) is lacking. The present study explores the association between birth seasonality and GDM in East China.This retrospective cohort study was conducted at the International Peace Maternal and child health hospital between 2014 and 2019. A total of 79, 292 pregnant women were included in the study after excluding participants with previous GDM, stillbirth, polycystic ovary syndrome, and lack of GDM laboratory records. The multivariate logistic regression model was employed to estimate the odds ratio and 95% confidence interval. After log transformation of blood glucose level, the percentage change and 95% confidence interval were estimated by a multivariate linear model.The risk of GDM among pregnant women born in spring, autumn, and winter was not significantly different compared to that among participants born in summer. Pregnant women born in autumn had significantly higher 1-hour postprandial blood glucose (PBG-1h) and 2-hour postprandial blood glucose (PBG-2h) levels than pregnant women born in summer. Compared to pregnant women born in August, the PBG-1h level of pregnant women born in October, November, and December increased significantly, whereas the PBG-2h levels of pregnant women born in November and December increased significantly.Pregnant women born in autumn exhibit higher postprandial blood glucose levels during pregnancy than in those born in summer. The findings provide evidence that exposure to seasonal changes in early life may influence blood glucose metabolism during pregnancy. Gestational diabetes mellitus (GDM) is a common pregnancy complication. Emerging evidence shows that nearly 1% to 30% of pregnant women experience GDM worldwide –4. ReducThe impact of prenatal environmental exposure on the risk of type 2 diabetes in adulthood is of increasing concern. Studies have demonstrated that an unfavorable prenatal environment may increase the risk of future health conditions whose outcomes are related to diabetes or GDM . EvidencThe season or month of birth is a surrogate factor for potential environmental exposure during the perinatal period. Factors associated with seasonal changes include but are not limited to temperature, sunshine, food supply, eating habits, outdoor sports activities, vitamin D synthesis, breastfeeding, infection status, etc –13. AlthThe study investigated a retrospective cohort from International Peace Maternity and Child Health Hospital, affiliated with Shanghai Jiaotong University School, from January 2014 to December 2019. Information of 94, 942 medical records from the electronic medical record system, including blood glucose levels, demographic data , disease history, pre-pregnancy BMI, smoking, drinking, birth history , etc. were retrieved. The exclusion criteria included pregnant women with no available date of birth, no GDM diagnosis record, previous GDM, multiple births, stillbirths, and abortions. Eventually, 79, 292 pregnant women were investigated  was used to diagnosis GDM at 24-28 weeks of gestation according to the recommendations of the International Association of the Diabetes and Pregnancy Study Groups (IADPSG) . PregnanThe birth season was classified based on astronomical seasons . To assess the effect of seasonal variation in birth on GDM, logistic regression analysis was performed with month and season of birth as the predictor. The reference group was set as the category with the lowest risk of GDM to birth month  and birth season (Summer). The multivariate logistic regression model of the association between GDM risk and birth season or birth month was adjusted for pregnancy age (years), fetal sex , the education level , drinking , smoking , family history of diabetes , pre-pregnancy BMI , parity (1 and ≥2), and gravidity , conception method , medical insurance type , ward type , etc.Logistic regression analysis was conducted after stratification for birth cohort , parity , type of registration , and pre-pregnancy BMI . Log-transformed blood glucose levels  at 24-8 weeks served as the outcome for linear regression analysis in exploring the influence of birth month and birth season on blood glucose. The blood glucose level was closer to a normal distribution after log-transformation , including Spring , Summer , and Autumn , Winter , was investigated. To exclude the effect of birth season of offspring on the association between maternal birth season and GDM, we took the pregnancy season as the covariate in the above analyses. The pregnancy season was classified based on astronomical seasonsR software (Version: 3.6.3) was employed for data analysis. Statistical significance was set at two-tailed P<0.05.Of the 79,296 pregnant women were included in this study, the average age of pregnancy was 30.54 ± 3.88 years, the average pre-pregnancy BMI was 20.97 ± 2.75. As shown in According to the multivariate-adjusted model, the birth season and month were not significantly associated with the risk factors of GDM 2. No suCompared to pregnant women born in summer, those born in spring, autumn and winter exhibited no significant difference in fasting blood glucose between 24-28 weeks of gestation ; National Key Research and Development Program of China (2019YFC1005106); Appropriate technology project of International Peace Maternity and Child Health Hospital of China Welfare Institute (CR2018SY02).The authors declare that the research was conducted in the absence of any commercial or financial relationships that could be construed as a potential conflict of interest.All claims expressed in this article are solely those of the authors and do not necessarily represent those of their affiliated organizations, or those of the publisher, the editors and the reviewers. Any product that may be evaluated in this article, or claim that may be made by its manufacturer, is not guaranteed or endorsed by the publisher.


Early life is marked by distinct and rapidly evolving immunity and increased susceptibility to infection. The vulnerability of the newborn reflects development of a complex immune system in the face of rapidly changing demands during the transition to extra-uterine life. Cytokines and chemokines contribute to this dynamic immune signaling network and can be altered by many factors, such as infection. Newborns undergo dynamic changes important to health and disease, yet there is limited information regarding human neonatal plasma cytokine and chemokine concentrations over the first week of life. The few available studies are limited by small sample size, cross-sectional study design, or focus on perturbed host states like severe infection or prematurity. To characterize immune ontogeny among healthy full-term newborns, we assessed plasma cytokine and chemokine concentrations across the first week of life in a robust longitudinal cohort of healthy, full-term African newborns.We analyzed a subgroup of a cohort of healthy newborns at the Medical Research Council Unit in The Gambia . Peripheral blood plasma was collected from all study participants at birth (day of life (DOL) 0) and at one follow-up time point at DOL 1, 3, or 7. Plasma cytokine and chemokine concentrations were measured by bead-based cytokine multiplex assay. Unsupervised clustering was used to identify patterns in plasma cytokine and chemokine ontogeny during early life.We observed an increase across the first week of life in plasma Th1 cytokines such as IFNγ and CXCL10 and a decrease in Th2 and anti-inflammatory cytokines such as IL-6 and IL-10, and chemokines such as CXCL8. In contrast, other cytokines and chemokines  remained unchanged during the first week of life. This robust ontogenetic pattern did not appear to be affected by gestational age or sex.Ontogeny is a strong driver of newborn plasma-based levels of cytokines and chemokines throughout the first week of life with a rising IFNγ axis suggesting post-natal upregulation of host defense pathways. Our study will prove useful to the design and interpretation of future studies aimed at understanding the neonatal immune system during health and disease. NewboCytokines and chemokines are low-molecular-weight proteins and key immune signaling molecules with pleiotropic effects on innate and adaptive immune responses –5. ActinHuman plasma contains basal concentrations of a range of cytokines and chemokines ,7. In adInterest in defining cytokines and chemokines in early life is driven in part by the distinct vulnerability of the newborn. 44% of under 5-year mortality occurs within the neonatal period, with ~75% of all newborn deaths occurring in the first week of life . FurtherPrior studies of plasma cytokine and chemokine concentrations in infants and/or children have been limited by small sample size (n < 20)  as well The objective of this study was to characterize the normal ontogeny of plasma cytokines and chemokine concentrations in a healthy, term African infant cohort over the first week of life. Such an effort provides insight into normal development and may inform future studies of variance from usual plasma cytokine/chemokine trajectories in the context of early life disease. Using a standardized, multiplex-based assay, we measured a diverse range of cytokine and chemokine profiles and utilized time series clustering to define ontogenetic trajectories during normal neonatal development. We found that plasma cytokine and chemokine concentrations clustered into distinct kinetic groups, including a rise in IFNγ-related cytokines across the first week, suggesting a coordinated ontogeny across the first week of human life.2.2.1.clinicaltrials.gov as NCT03246230. In brief, mothers-infant pairs were consented and enrolled at time of delivery at the Medical Research Council (MRC) Unit at the London School of Hygiene and Tropical Medicine in The Gambia. HIV- and Hepatitis B-negative mothers 18 years or older, were enrolled. Infants were enrolled if >36 weeks of gestational age , with Apgar scores >8 at 5 min and birth weight >2.5 kg. Peripheral blood samples (max volume 2 ml) were collected from infants using sterile sodium heparin tubes (Becton Dickinson). Four time points were collected: Visit 1 (V1), was collected within the first 24 h of life (Day of Life (DOL)0); while the Visit 2 (V2) sample was collected at either DOL1, or DOL3, or DOL7. Plasma samples were processed for analysis as previously published [The clinical protocol for this study EPIC002 has been previously described,39. The ublished . All pla2.2.Milliplex Human Cytokine/Chemokine MAGNETIC BEAD Premixed 41 Plex Kit. (Millipore cat. #HCYTMAG-60K-PX41), Dulbecco’s phosphate-buffered saline , and Corning Cell-BIND® 384 well plates (cat. #CLS3764).sCD40L, EGF, FGF-2, Flt-3 ligand, Fractalkine, G-CSF, GM-CSF, GRO (CXCL1), IFN-α2, IFN-γ, IL-1α, IL-1β, IL-1ra, IL-2, IL-3, IL-4, IL-5, IL-6, IL-7, IL-8 (CXCL8), IL-9, IL-10, IL-12 (p40), IL-12 (p70), IL-13, IL-15, IL-17A, IP-10 (CXCL10), MCP-1 (CCL2), MCP-3 (CCL7), MDC (CCL22), MIP-1α (CCL3), MIP-1β (CCL4), PDGF-AB/BB, RANTES (CCL5), TGF-α, TNF-α, TNF-β, VEGF, Eotaxin (CCL11), and PDGF-AA. Plasma samples were assayed using a 384-well plate platform following the manufacturer’s instructions, including the provided controls. Samples were analyzed using a Flexmap 3D system with Luminex xPONENT software .The Luminex assay was performed across 7 Luminex plates. Plasma was diluted 1:2 in dPBS. Cytokines and chemokines were measured using the 41-plex Millipore Milliplex Map Kit (cat. #HCYTMAG-60K-PX41), which contains; The xPONENT software files were processed using the drLumi R package. We fitted 4-parameter logistic, 5-parameter logistic, and exponential functions to the dilution series data for each analyte using the scluminex function implemented in drLumi (drLumi::scluminex), selecting the best fit function in each case. These were then used to determine the lower and upper limits of detection and quantification for each analyte and plate. Analytes that fell below or above these values were imputed to the lower or upper limit of quantification, respectively. For a given sample and analyte, if readings were <30 beads, concentration values were discarded. Samples with all analytes below the lower limit of detection (LLD) were also excluded from analysis.2.3.Cytokine and chemokine values were log transformed. ComBat (R package) was used to carry out batch-correction  across plates based on plate-specific bias identified by PCA. A universal reference standard sample set was added to each plate and used as a bridge sample set across plates.Cytokines or chemokines with near-zero variance were identified using the nearZeroVar function from the caret R package . Near-zero variance cytokines  had few values above their respective LLD and were excluded.10-transformed cytokine concentration and fold change datasets, using R packages FactoMineR_2.3 and factoextra_1.0.7. All cytokines were centered and scaled to unit variance.Principal component analysis (PCA) was employed to summarize variability in the log10-transforming. P-values < 0.05 were considered significant, and the Holm-Bonferroni method using n = 38 cytokines was used to adjust for multiple comparisons. Associations of cytokines with biological sex, ethnicity, maternal age, and gestational age were tested to assess if there were any other factors with significant effects on cytokine concentrations. Each cytokine was modeled as a dependent variable in separate linear models, with the variable of interest, a Visit term, and an interaction term as independent variables.Statistical differences in cytokine levels between DOL were assessed using the Wilcoxon signed-rank test. Fold-change values were calculated by indexing untransformed concentration values to DOL0, then log10-transformed cytokine concentrations were first standardized. Average time series were constructed by taking the mean of each cytokine at each DOL. The distances between cytokine time series were calculated with dynamic time warping, using the R package dtw_1.21–3 [To identify groups of cytokine and chemokines with common trajectories across the first week of life, we performed time series clustering. The logw_1.21–3 . This apTo assess the robustness of our clustering approach, we repeated the procedure across 1000 bootstrap re-samplings using 90% of the data (random selection of 540 out of the 608 participants), and used the frequencies with which cytokines co-clustered to calculate the final groupings, as previously described. In addi3.3.1.608 healthy Gambia mother-newborn pairs from the EPIC-002A cohort were analyzed in this study. The cohort demographic table  indicate3.2.Initially, we investigated the associations between plasma cytokine and chemokine concentrations and physical findings at birth, as these can be early indicators of post-natal conditions . There were no significant differences observed in plasma concentrations cytokines and chemokines in relation to respiratory rate, heart rate, weight, length, head circumference, or temperature at birth (data not shown).We also examined the correlation between plasma cytokine and chemokine concentrations and demographic clinical data over the first week of life. No significant correlations were observed between demographic parameters such as sex, maternal age, gestational age or breastfeeding with cytokines and chemokines measured at DOL 1, 3, or 7.3.3.To identify potential ontogenetic changes, we measured the concentration of the plasma cytokines and chemokines in 608 healthy Gambia mother-newborn pairs  over the first week of life. Principal component analysis (PCA) demonstrated the expression of cytokines and chemokines. The first two principal components (PC1 and PC2) accounted for 35.4% of total variance . PC2 cap3.4.We tested whether the relative abundances of individual cytokines and chemokines changed across the first week of life . At DOL13.5.Time series clustering highlighted specific patterns of plasma cytokine and chemokine concentrations over the first week of life . HierarcAs a sensitivity analysis, we compared our cluster method to an independent validation method. We comp10-as well as raw-concentrations and depicted in Representative cytokines and chemokines for each cluster are shown in 4.In this study, plasma cytokines and chemokines were measured in a longitudinal cohort of healthy, full-term Gambian newborns throughout the first week of life, using highly standardized, quantitative multiplex protein assays. A variety of longitudinal changes were observed. Plasma concentrations of CXCL10, GM-CSF, IFNγ, and IL-5 increased over the first week of life while those of CCL4, CXCL8, G-CSF, IL-10, IL-1RA, IL-6, and TGFα decreased. We thus observed that ontogeny is a strong driver of human neonatal plasma cytokine and chemokine concentrations.Cytokines and chemokines are key signaling proteins that act via cognate receptors to shape immune responses . In earlNewborns emerge out of a highly regulated maternofetal environment aimed at protecting non-self (the fetus) from self, the maternal immune system, while in utero. For example, the placenta produces mediators such as progesterone and prostaglandin to promote a Th2 bias in the fetus ,51. HumaAlthough the in utero environment is highly tolerogenic, due to a variety of immunosuppressive mechanisms –54, birtAfter birth, the immune system begins to transition towards a complex and microbe-rich extra-uterine environment. The establishment of the gut microbiome begins at birth and contWe did not observe any significant differences in cytokine concentrations between infants who were breastfed vs those who were formula feed (data not shown). Despite this observation, it remains possible that breast milk cytokine concentrations may impact those of in infant plasma,63, as: Consistent with other studies of cytokines and chemokines in early life ,65, we dGiven growing evidence of rapid changes in infant immunity , our stuOur results have potential translational applications. Compared to adults, infants have increased susceptibility to infection, yet most preventative strategies for neonates rely upon our understanding of the adult immune system. Inflammatory protein markers such as those regulated by IL-6, like C-reactive protein (CRP), are important clinical analytes for early onset neonatal sepsis ,70. In iThe age-dependent changes observed here suggest that plasma cytokines and chemokines have day of life-specific normal ranges, with future studies needed to further validate this finding. We observed a clear plasma cytokine/chemokine ontogeny signature during the first week of life. As cytokines, such as IFN-γ and IL-1β, can contribute to “innate memory” or trained immunity 7475, fOur study also has a number of limitations. Although the number of infants included in this study is substantial, samples were collected at a single study site in The Gambia (West Africa), requiring further studies to assess the generalizability of these findings. Nevertheless, our observation of significant changes in the cytokine IFNγ and related chemokine, the IFNγ-inducible CXCL10, with similar trajectories noted in geographically and genetically distinct newborns in Papua New Guinea  suggests5.Our findings demonstrate an age-dependent pattern of plasma cytokines and chemokines in healthy, term Gambian infants, representing an ontogenetic trajectory reflective of the initiation of a post-birth transition from a Th2-polarized to a more balanced Th1/Th2 immune state. Our findings help define the baseline trajectories of plasma cytokines and chemokines in healthy newborns and will inform future studies to correlate plasma cytokines and chemokines with responses to immune challenge such as immunization, as well as deviations from healthy trajectories due to infection or other diseases.Supp.materials


BackgroundOn March 3, 2020, the first case of coronavirus disease (COVID-19) was reported by the Ministry of Health, Kingdom of Saudi Arabia. Within days, the government confirmed more cases and adopted lockdown measures with travel restrictions from March to June 2020. A distinctive coronavirus was isolated from 190,823 patients by June 30. The pandemic resulted in a significant risk to public health. The study aimed to evaluate the impact of COVID-19 lockdown on the rate of premature births.MethodIn this cross-sectional study, we observed premature births at the Neonatal Intensive Care Unit (NICU). The study site is a 1,500-bed teaching hospital, with around 4,500 annual deliveries, 70 beds in level II and level III, and tertiary care NICU. We compared the birth rates among preterm infants between March 1 to June 30, 2017-2019, to the similar calendar months of 2020. Information on nationality, gestational age, and maternal conditions were collected from the medical records. We used the Poisson regression model to assess the preterm birth rate's temporal trends before lockdown versus during lockdown.ResultsAmong 7,226 total live neonates, we recorded 1,320 preterm infants during the study period of 2017-2020. The preterm birth rate per 1,000 live births during lockdown showed a 23% drop in the overall preterm birth rate with Prevented Fraction of 36% in extremely preterm  births and 26% in moderate/late premature  births. The estimated preterm birth rate among the Saudi expats  showed an increased tendency compared to Saudi nationals  and was statistically not significant during the strict lockdown.ConclusionThere was a significant reduction in the birth rate of extremely preterm and moderate/late preterm infants during lockdown when compared to the preceding three years. A national dataset is required to evaluate the extent of lockdown's impact on the preterm birth rate. Preterm birth (PTB) is defined as a live birth before completing 37 weeks of pregnancy. PTB across nations remains a leading cause of infant mortality and morbidity, which adds significant challenges to their health and quality of life compared to term neonates .The majority of PTB is spontaneous preterm birth . Other cIt remains unclear which intervention is best to prevent spontaneous preterm births in women with risk factors . The majWheeler et al. reported positive benefits from family support on reducing PTB rates . Also, tSaudi Arabia's Ministry of Health (MOH) worked to achieve the concepts related to providing recovery, harmony, and sustainability to the health system. It launched educational campaigns for the public to follow strict hand-hygiene measures, social distancing, and adherence to MOH recommendations and as a collective effort to reduce the transmission of coronavirus disease COVID-19). A nationwide curfew was adopted from March to June 2020 with the temporary closing of shops, colleges, schools, and all non-essential institutions. The lockdown occurred in two phases: complete lockdown in phase 1 with restricted mobility and travel by air, land, and sea for 24 hours, followed by 8 and 5 hours in phase 2 partial quarantine [. A natioWe conducted this cross-sectional study at the Neonatal Intensive Care Unit (NICU), Public Sector Children Hospital - King Saud Medical City (KSMC), covering four referral hospitals and 10 primary healthcare centers in Saudi Arabia. The inclusion criteria were all live infants born at KSMC between March 1 till June 30, 2017-2020, and the exclusion criteria were abortions, stillbirths, and intrauterine fetal death (IUFD). We collected data on live births, PTB, gestational age in weeks, and maternal details, including maternal conditions and nationality  for the study period from the hospital logbook of delivery. We categorized the 1,320 preterm infants according to gestational age at birth as extremely preterm (24-27 weeks + 6 days), very preterm (28-31 weeks + 6 days), and moderate to late preterm (32-36 weeks + 6 days).The Institutional Review Board approved the present study as per the National Bioethics rules and regulations (H1RI-30-Jun20-01). The data was analyzed using SPSS 25.0 . The variables under study were categorical and presented as frequency and percentage. Here, we used the One-Sample Test for Binomial Proportion, Chi-Square, Normal-Theory Method, Fisher's Exact (Clopper-Pearson), and 95% confidence interval (CI) for the statistical significance. The Poisson regression model was derived to assess the preterm birth rates' temporal trends per 1,000 live births over 16 months. We compared these estimates for March-June 2020 with the 95% Wald confidence interval and risk ratio analysis with the previous years. Our study identified 7,226 live births during the study period from March 1 to June 30 of 2017-2020, with 3,832 (49.6%) male and 3,894 (50.4%) female infants. We estimated the overall PTB rate per 1,000 live births for the pre-lockdown period (March-June of 2017-2019) and the nationwide lockdown (March-June of 2020) as exhibited in Figure This figure established an increase of 19% in total live births between 2017 to 2019, with a 10% decrease from 2019 to 2020. PTB rate per 1,000 live births showed a 7% decline from 2017 to 2018 and a 23% decrease during the COVID-19 lockdown period in 2020. We also analyzed the data based on ethnicity into two groups - Saudi nationals and Saudi expats. The PTB rate was more among Saudi expats than Saudi nationals, with significant differences during March and June of 2020 . We observed a reduction of the PTB rate per 1,000 live births in both populations, with more significant among Saudi expats  based on the Chi-square test for proportions; however, it was not statistically significant  with the lockdown period (2020) and tested for its significance Table . The preOur study, conducted in a tertiary hospital in Riyadh, Saudi Arabia, showed a significant reduction in preterm birth rates during quarantine in two groups, extremely premature and late preterm, compared to a control group of correlating calendar years from 2017-2019. However, we did not identify a statistically significant reduction in the overall PTB rate Table .Similar observations have been reported in multiple studies conducted in Ireland, Denmark, Australia, and the Netherlands with differences in the impacted age groups , which may imply an international reduction trend of PTB. Researchers from Denmark observed a 90% reduction in extremely premature neonates  when compared to the previous five years . In a prThe reduction we observed in our study can be unrelated to the event of lockdown but explained by the singleton pregnancy in our data during quarantine (P=0.0136) and decreased maternal disorders related to threatened preterm labor (P= 0.0311) Table . LimitatThis study evaluates the effect of Saudi national lockdown on the rate of preterm births. The significant reduction observed in extremely premature and moderate/late premature birth rates anticipates a reduction of morbidity and mortality as well as reduced burdens on families and medical staff, especially in regards to the extremely premature group. Similar reports from studies conducted in Ireland, Denmark, and Australia during the lockdown period would hint at valuable future research opportunities that can aim to discover modifiable PTB risks. Further studies on lifestyle, behavioral, physical, and psychosocial modifications adopted by pregnant women during the lockdown would illustrate a better understanding and aid in devising new guidelines and preventative measures for future pregnancies.


We test this possibility using the odds of a live-born twin among male births in Norway as an indicator of the depth of selection in birth cohorts.The suspicion that a population stressor as profound as the COVID-19 pandemic would increase preterm birth among cohorts in gestation at its outset has not been supported by data collected in 2020. An evolutionary perspective on this circumstance suggests that natural selection We apply Box–Jenkins methods to 50 pre-pandemic months to estimate counterfactuals for the nine birth cohorts in gestation in March 2020 when the first deaths attributable to SARS-CoV-2 infection occurred in Norway. We use Alwan and Roberts outlier detection methods to discover any sequence of outlying values in the odds of a live-born twin among male births in exposed birth cohorts. We find a downward level shift of 27% in the monthly odds of a twin among male births beginning in May and persisting through the remainder of 2020.in utero, birth cohorts exposed in utero to the onset of the COVID-19 pandemic yielded fewer male twins than expected.Consistent with evolutionary theory and selection Our finding of fewer than expected male twin births during the onset of the COVID-19 pandemic provides more evidence that evolution continues to affect the characteristics and health of contemporary populations. Constants and autoregressive parameters all exceeded twice their standard errors.In which [a priori—from the dependent variable before measuring its association with the ‘interruption’ . Our test, therefore, ‘controls’ for autoregression at 2 and 7 months for males and females respectively even though we did not predict this autocorrelation a priori.As noted above, to satisfy the assumptions of statistical estimation of association, time-series modeling removes all forms of autocorrelation—whether or not hypothesized in utero in Norway. If so, the unexpectedly low rates of preterm birth observed in 2020 may reflect, at least in part, spontaneous abortion of fetuses that in more benign times would have survived to live birth later in pregnancy but before 36 complete weeks of gestation.We find evidence that, consistent with theory, the onset of the COVID-19 pandemic and the steps taken to avert its worst effects, may have deepened selection in utero [Norway experienced relatively low rates of SARS-CoV-2 infection and excess mortality during our test period, making it a good setting in which to estimate the association between social processes, as opposed to infection, and twin births. The pandemic could have engendered stress not only by threatening and causing infection, but also by imposing demands on individuals and households (e.g. caring for children out of school or ill relatives) while also disallowing access to social resources (e.g. supportive co-workers), and constraining access to settings  that Norwegians would otherwise rely on for effective restoration. We, however, have no measurements of access to social and other coping resources in Norway during the pandemic. We cannot, therefore, estimate whether an increase in infection or a decrease in protective or restorative resources better ‘fits’ the drop in twin births that we found. We note, though, that previous studies with Norwegian and Swedish data have found indications of higher rates of spontaneous abortion under stressful circumstances that do not involve infection , 43–45. in utero . The panin utero .2 dipped nearly 10 μg/m3 below pre-COVID-19 levels [We further note that pandemic management strategies may have reduced the dose of a least one ambient stressor, traffic-related air pollution (e.g. nitrogen dioxide) , thought9 levels . Our finin utero appeared most susceptible to the COVID-19 pandemic. Data on gestational age of live births and spontaneous losses would allow the creation of a time series arrayed by estimated month of conception (rather than by month of birth). Such series would allow identifying which conception cohorts contributed most to our birth cohort findings. That information would, in turn, suggest the gestational age at which stressors on the population trigger selection in utero against male twins.Limitations of our tests include that we cannot know the gestational age, or ages, at which twins Pandemics, by axiom, affect most human populations. That fact, and the lack of twin birth data from other societies, precludes our using a comparison population design to control for generally occurring confounders . The perInterventions in Norway intended to increase social distancing early in the pandemic included suspending medically assisted reproduction (MAR) services . Twins, in utero. We and others have argued that this literature leads to the prediction of fewer than expected twins among male births in stressed populations. Other literature may also lead to the prediction and suggest other lines of further research. Work describing competition between twins for resources in utero [We were led to our hypothesis by theoretical and empirical literature arguing that natural selection conserved biological mechanisms that manifest in reproductive suppression, brood reduction, offspring sex selection and selection in utero  could, fa priori on any dimension of dose. If this were possible, future research could test the intuitively appealing argument that differences in the strength of association reflects not only differences in the characteristics of the populations tested, but also in the dose of stress they likely suffered.Although multiple studies have supported the argument that twins will appear less frequently than expected among males born to stressed populations, the stressors tested vary widely in their nature as do the reported effect sizes. No work has yet attempted to array the stressors in utero shapes the characteristics of human birth cohorts and that collective as well as individual choices likely affect the targets and depth of that selection [in utero.We cannot claim that our findings have clear clinical implications although they suggest increasing, during stressful times, public health programming focused on women of reproductive age. Our findings do, however, have implications for our understanding of how evolution affects the nature and experience of contemporary populations. They call attention to the facts that selection election . They, mConflict of interest: None declared.


Being born and giving birth have received little sociological appreciation so far, although they are fundamental everyday events. In the last decade, the German language literature on the subject comprises only one extensive publication and a few articles  that are unnecessary and not medically indicated, unnecessarily frequent or unnecessarily rough or painful examinations, gross extraction or tearing of the placenta, the so-called Kristeller maneuver , unnecessary induction of labor with labor-promoting agents, and generally restricting the freedom of movement of the woman in labor when she experiences such restriction as unnecessary (e.g. by strapping her to leg restraints or using a continuous cardiotocography) Imlau . One of In German-speaking countries, where the discussion is currently prominent, the concept of trauma is particularly central. In parallel with the trauma discourse, “doulas”, psychosocial birth companions, are becoming established and are now increasingly offering their services to women in Switzerland, Austria, and Germany Doula CH : “Doulas1. The Federal Office of Public Health (FOPH), the Federal Statistical Office (FSO) and the Swiss Health Observatory (Obsan) do not have suitable data on this topic. 2. The Federal Council has no evaluable data on practice in the gynecological and obstetric context, since quality assurance in this area is the responsibility of the professional societies. How the issues raised in the report from France could be analyzed for Switzerland would need to be examined in more depth in collaboration with the professional societies. 3. The medical statistics of hospitals (MS) contain data on the number of episiotomies performed during deliveries in Switzerland. In 2017, 9906 perineal incisions were performed during natural births. The trend is downward: while in 2012 an episiotomy was performed in 25 percent of natural births, in 2017 the figure was 17 percent  has data from freelance midwives  on birth injuries. According to the GDV, data for the years 2002 to 2014 were analyzed and actuarially evaluated as part of a calculation project. According to this, it does not make sense to show individual years due to the small number of claims. These fluctuate between six and 31 for the period from 2004 to 2014. On average, about 20 birth claims are reported per year to the professional liability of freelance midwives.  and an increasing rate of intervention, especially cesarean sections, which may explain the increase in obstetric violence. This is related to the second dimension, which is the general economization of clinics. This includes diagnosis-related fixed-sum billing and the privatization of clinics, which also affect the staff and result in clinics being run according to an entrepreneurial logic Jung . ProfessIn conclusion, notions of normality regarding birth experiences seem to be shifting. The painless, complication-free, and as natural as possible birth that some expect today is in contrast with the reality in delivery rooms, where structural resources, especially time for individualized care, are scarce. This can leave subjects feeling disappointed, alienated, or even traumatized. It seems that the professions involved in birth today are no longer only responsible for attending births (midwives/doulas) and the medical care of women during birth (physicians) but are also expected to be responsible for a good and successful birth experience cf. Jung . This spBodies that Birth (2018) by sociologist Rachelle Chadwick and Sarah Eckardt reviews the edited volume on “feminist perspectives on parenthood” (2022) by Lisa Y. Haller and Alicia Schlender. We wish to continue our exchanges and collaborations on this subject and particularly look forward to future meetings in person, which had to be deferred due to the pandemic.Lotte Rose’s contribution deals with the dispositives of responsibilization, optimization, and neoliberalization in the context of birth and thereby constituted (new and old) gender orders. Sarah Eckard empirically examines these dispositives, as well as others such as self-responsibility and risk, as subjects of individual birth experiences and interpretations. Christiane Winkler and Emine Babac address childbirth and birth experiences from an intersectional perspective, especially with regard to inequalities in health care for pregnant women and women giving birth and their implications for obstetric practice. Julia Böcker examines contemporary discourses and experiences related to stillbirth, and Mariette Mayrhofer-Deak reviews the monograph


The aim of this study was to examine the association between periconceptional folic acid (FA) supplementation and risk of preterm birth.We conducted a retrospective cohort study in women aged 18–49 who participated in the NFPHEP from 2010 to 2018, and had a singleton livebirth in 129 counties in southwest China. Participants were divided into four groups according to the time period starting FA use: no use, after the last menstrual period, at least 1–2 months before the last menstrual period, at least 3 months before the last menstrual period. The outcomes were preterm birth (gestation < 37 weeks) and early preterm birth (gestation < 34 weeks).201,477 women were included and 191,809 (95.2%) had taken FA during periconception. Compared with women who did not take FA, women who started taking FA 1–2 months before their last menstrual period had a 15% lower risk of preterm birth , and women who started taking FA at least 3 months before their last menstrual period had a 20% lower risk of preterm birth , but women who started taking FA after their last menstrual period did not appear to reduce the risk of preterm birth.In this study of 200,000 Chinese women, periconceptional supplementation with FA was associated with a lower risk of preterm birth. Women who started taking FA at least 3 months before their last menstrual period were more likely to reduce the risk of preterm birth. Folic acid (FA) is a water-soluble member of the vitamin B complex family, and it has an essential role in DNA methylation and synthesis , 2. PrevPreterm birth complications are the leading cause of death among children under 5 years of age . ApproxiWith a large population and a large number of births, China has the second greatest number of preterm births in the world , so addrWe did a population-based retrospective cohort study in women of childbearing age 18–49 years) who participated in the National Free Preconception Health Examination Project (NFPHEP) from Jan 1, 2010, to Dec 31, 2018, and had a singleton livebirth in 129 counties in southwest China. NFPHEP was launched by the Chinese National Health and Family Planning Commission in 2010. It aims to provide free health examinations and other services before conception for couples who planned to become pregnant in the next 6 months, as well as follow-up in their first trimester of pregnancy and after delivery. This study was approved by the Institutional Review Board of the Chinese Association of Maternal and Child Health Studies. All participants provided written informed consent before enrolment [–49 yearsTrained qualified local health workers registered couples of childbearing age who were planning to become pregnant in the next 6 months and used the standardized questionnaire to collect baseline information from women of childbearing age, including sociodemographic characteristics ; history of pregnancy and adverse pregnancy outcomes ; history of chronic disease . Health workers measured height and weight of participants and calculated the body mass index (BMI) by dividing the weight in kg by the square of the height in m. Meanwhile, venous blood was extracted from the participants by qualified and trained professionals, and serum samples were separated and tested in the laboratories of accredited medical institutions. The concentration of hemoglobin was measured using the cyanide methemoglobin method. In this study, the diagnostic criteria for anemia referred to the diagnostic threshold recommended by WHO (anemia was defined as lower than 120 g/L for non-pregnant women) and adjusted according to altitude . All samMaternal and child health workers interviewed participants face-to-face or by telephone in 3 months after conception, recording their last menstrual period, their supplemental use of FA, their living habits of eating meat and eggs, eating vegetables, smoking, and drinking alcohol during pregnancy. All participants were followed up by health workers for 1 month after delivery to collect information including pregnancy outcome , delivery date, gestational weeks, and newborn information (singleton or multiple births). The study was terminated when participants had preterm birth or other pregnancy outcomes, or when the study reached the end of the observation period .In this study, we defined the use of FA supplement as taking 1 tablet (0.4 mg) of FA a day. Participants were divided into four groups according to the time starting FA use: no use (control group), after the last menstrual period (exposure group I), at least 1–2 months before the last menstrual period (exposure group II), at least three months before the last menstrual period (exposure group III).The primary outcome was preterm birth which was defined as a delivery from 28 weeks to less than 37 weeks of gestation. Early preterm birth was defined as a delivery from 28 weeks to less than 34 weeks of gestation. Preterm and early preterm birth rates were the proportion of premature and early premature births in the total number of all singleton livebirths, respectively.2 test was used for inter-group comparison.We included all women who fitted all inclusion criteria, and described the distributions of FA using time of the participants in different sociodemographic characteristics , history of pregnancy and adverse pregnancy outcomes , physical condition , living habits during pregnancy . The χ2, 18.5–23.9 kg/m2, 24.0–27.9 kg/m2, or ≥ 28.0 kg/m2), anemia (yes or no), and HBsAg (positive or negative). In model D, we additionally adjusted for living habits during pregnancy, including eating meat and eggs (yes or no), eating vegetables (yes or no), smoking (yes or no), and drinking alcohol (yes or no). Then the adjusted ORs and 95% CIs for supplementation with FA and preterm, early preterm birth were obtained.Our study used the univariate logistic model to obtain crude odds ratio (cOR), and used multivariate logistic model to adjust the potential risk factors for preterm birth and obtained adjusted odds ratio (aOR) and 95% confidence intervals (95% CI) for FA supplementation and preterm, early preterm birth rates. To test the robustness of the results, we adjusted different covariates in stages. In model A, we adjusted for sociodemographic characteristics of participants, including age ; ethnicity ; level of education ; and occupation . In model B, in addition to those factors included in model A, the history of pregnancy and history of adverse pregnancy outcomes were also adjusted, including first gestation (yes or no), primipara (yes or no), history of preterm birth (yes or no), history of abortion (yes or no), and history of stillbirth (yes or no). In model C, in addition to those factors included in model B, we also adjusted for physical conditions of participants, including BMI ; 1146 women with genital tract infectious disease. 201,477 women were included in the final study  had taken FA during periconception. Women aged 18–20 years, of Miao, Hani ethnicity and other ethnic minorities, with primary education and below, with BMI ≥ 28.0 kg/mP < 0.05). Multivariate logistic models showed that after adjusting for covariates, compared with women who did not take FA, women who started taking FA 1–2 months before their last menstrual period had a 15% lower risk of preterm birth, and women who started taking FA at least 3 months before their last menstrual period had a 20% lower risk of preterm birth. After adjusting for different variables, the aORs obtained by models A, B, C and D were relatively robust . Univariate regression showed that the starting time of FA supplementation in women was associated with preterm birth . Multivariate logistic models showed that after adjusting for covariates, women who had taken FA during periconception had a lower risk of early preterm birth than women who did not take FA, with significant results (P < 0.05). The adjustment of different covariables did not affect the results, and the results of the four models were robust . Women who did not take FA, who started taking FA after their last menstrual period, who started taking FA 1–2 months before their last menstrual period, and who started taking FA at least 3 months before their last menstrual period had an early preterm birth rate of 3.6%, 3.1%, 2.9% and 2.7%, respectively, with a significant decrease (P > 0.05).In the sensitivity analyses, the associations between the time of FA supplementation in periconceptional women and preterm birth did not change significantly in different baseline characteristics . Compared to other exposure groups, the protective effect of starting taking FA at least 3 months before the last menstrual period was stronger Fig. . HoweverPreterm birth is a global public health. It is estimated that the global preterm birth rate in 2014 was about 10.6% (9.0–12.0%), equating to an estimated 14.84 million live preterm births, of which the preterm birth rate in Asia was about 10.4% [Previous studies have shown inconsistent associations between FA supplementation during periconception and preterm birth. The 1999–2012 Jiaxing Birth cohort showed that among 240,954 women, FA supplementation was associated with lower risk of preterm birth, and the association was only significant in pre-conceptional FA supplementation  . A case–P > 0.05) [Some studies have not found an association between FA supplementation and preterm birth in women. A prospective cohort study in America in 2015 involving 3,647 women found no association between FA supplementation and preterm birth ( > 0.05) . A syste > 0.05) . The ass > 0.05) . This asThe period around conception (2–3 months before and after) is a critical period for optimizing gamete function, and early placental development . Epidemis < 0.05). Similar results were found in the Lanzhou birth cohort, where FA supplementation was associated with a 50% reduction in early preterm birth compared to women who did not take FA [Our study also found that periconceptional FA supplementation could reduce the incidence of early preterm birth (gestation less than 34 weeks). Women who started taking FA after their last menstrual period, 1–2 months before their last menstrual period, and at least 3 months before their last menstrual period had a 14%, 19%, and 23% lower risk of preterm birth than women who did not take FA ( take FA .A large number of randomized trials have shown that supplementation with FA during periconception can prevent NTDs in newborns , 32. As Our study has several strengths. First, this study was a large population-based retrospective cohort study that recruited all women who participated in the NFPHEP and had a singleton livebirth from 129 counties of Southwest China between 2010 and 2018, which may have less selection bias. The information about exposure in this study was collected during the follow-up in their first trimester of pregnancy, thus reducing the recall bias as much as possible. In addition, this was the first explorative study of periconceptional FA supplementation and preterm birth in a large cohort in Southwest China. The cohort included more than 40 ethnic minorities living in the region, and our results are more representative of the multi-ethnic situation in China than other studies. However, our study has some limitations. The NFPHEP did not collect information on pregnancy complications such as gestational hypertension, gestational diabetes and, therefore, may influence the interpretation of the results to some extent.In this retrospective cohort study of 200,000 Chinese women, periconceptional supplementation with FA was associated with a lower risk of preterm birth. Women who started taking FA at least 3 months before their last menstrual period were more likely to reduce the risk of preterm birth than women who started taking FA 1–2 months before their last menstrual period.


At the present time, there is a growing interest in additive manufacturing (AM) technologies and their integration into current process chains. In particular, the implementation of AM for tool production in micro injection molding (µ-IM), a well-established process, could introduce many advantages. First of all, AM could avoid the need for the time-consuming and expensive fabrication of molds for small series of customized products. In this work, the feasibility, quality, and reliability of an AM/µ-IM process chain were evaluated by designing and fabricating mold inserts for µ-IM by stereolithography (SLA) technology; the mold inserts were characterized and tested experimentally. The selected geometry is composed of four thin cavities: This particular feature represents an actual challenge for both the SLA and µ-IM perspective due to the large surface-to-volume ratio of the cavity. Two different materials were used for the mold fabrication, showing sharply different performance in terms of endurance limit and cavity degradation. The obtained results confirm that the µ-IM process, exploiting an SLA fabricated mold insert, is feasible but requires great accuracy in material choice, mold design, fabrication, and assembly. Injection molding of micro or thin components is a widespread technology due to its capability of manufacturing low-cost and highly repeatable polymeric parts relevant to many different fields, from IT to healthcare to the biomedical sector. However, the high costs of mold design and manufacturing via conventional approaches based, i.e., on milling/EDM processes affect the development cycle and industrial uptake of new products. AM technologies offer several advantages with respect to traditional manufacturing for mold and insert fabrication, such as waste reduction, minimized energy consumption, reduced overall manufacturing time, and time to market. The company can adapt or adjust the new product design step by step according to the requirements assessed by the end users so that when a stable design is reached, the production can be scaled up and transferred to a mass production process, thus reducing the investment risk and the time to market. Furthermore, even if only a small series or single-unit batch are required, the additive manufactured mold could cause the injection process to be economically feasible ,2. The lAmong additive technologies for polymers, stereolithography is the process that best fits the compromise between quality (accuracy and surface finishing), cost, and ease of use. The “soft” materials, such as polymers, used in AM processes for mold fabrication present thermal and mechanical properties and toughness that are significantly different from those of steel, affecting both the tool durability at high temperature and the quality of the final products . In partAt a macro scale, the use of additive manufactured molds has been studied by different authors and the achieved results are different in terms of duration and quality of the parts due to the different applied additive technologies and materials. In terms of quality, comparing three mold prototypes for injection molding realized by different AM technologies , Leon-Cabezas et al.  found ouMore recently, new materials have been developed for several AM technologies, relaunching research on this topic. Dizon et al.  presenteAn experimental material characterization for mold insert applications was proposed by Etesami et al.  by measuConsidering the micro world, which this paper is focused on, some experimental works were already done in recent years, especially by Tosello et al., about the fabrication of bricks (dimensions 5 × 4 mm) and cylindrical pillars (height and diameter 200 µm) molded by soft tools carried out via digital light processing (DLP) technology. In particular, these authors focused on thermal numerical modeling for tool life evaluation , cost anIn this work, focusing on the field of micro-manufacturing, the combination of stereolithography mold manufacturing and the micro-injection process is proposed to take advantage of both techniques. A mold with four thin cavities with a large surface-to-volume ratio was chosen as the test case since it represents a challenge for both processes, SLA and µ-IM. The mold insert for the µ-IM process was designed following mold-insert design rules and the specifications of AM production, and then carried out via SLA with two different materials that are described later: grey resin (G) and high-temperature resin (HT). The two molds were characterized to evaluate the achieved dimensional and geometrical precisions of the stereolithography process and experimentally tested in the micro-injection molding machine to evaluate the replication capability and durability in terms of number of shots to failure (NSF), and thus the feasibility, accuracy, and reliability of the proposed SLA/µ-IM process chain. The proposed mold is composed of two main parts: the mold base, which is the main assembly structure equipped with all subsystems , and the mold insert with shaped cavities, injection feeding, and melt distribution (cold runners). Typically, both the mold base components and mold insert are made of steel and, as mentioned, their manufacture requires relevant design and machining time. In this work, the mold insert was fabricated by additive manufacturing, thus significantly shortening its fabrication time. The mold insert design is an important task in the development process since it should address issues of both fabrication (AM for mold insert fabrication) and final processing (μ-IM) technologies. The first step is the part assessment, which includes material selection, geometric features , and part design guidelines . When thThe designed mold insert presents four cavities radially distributed with a nominal depth of 100 μm, thin film gates, and one central cylindrical ejector pin with a nominal diameter of 1.3 mm, guided for a length of 5 mm. Filling these cavities without defects is already a challenge for the common micro-injection molding that uses a steel mold. The challenge is even greater for the combination of injection molding using an SLA mold, because of the mechanical and thermal properties of the resin mold and the need for relatively high temperature and pressure to fill the cavities. Limitations can also arise from the interaction between the resin insert and melt polymer. However, the design has the goal of defining a sort of metric by measuring the infill length to judge this unusual application. 2. The two gates are very close (1 mm), therefore the melt injection pressure will not differ between them if the cross sections are invariant. This design rule for thin film gates allows a uniform melt flow to the cavity without pressure drops, thus succeeding in filling. In this work, four challenging aspects arose: (i) filling of the thin cavities, (ii) part quality and accuracy, (iii) ejection of the part, and (iv) mold insert design for durability. In order to address the first issue (cavity filling), thin film gates were adopted to guarantee a full-width and uniform feeding of the melt polymer into the thin cavities. To this scope, starting from the central injection sprue with a diameter of 2.5 mm, the melt front was split into 4 gates 1 mm wide and 0.3 mm deep, which arrived at the cavities with gates 3 mm wide and 0.1 mm deep, therefore having a trapezoidal design with a distance between the two gates of about 1 mm. It is worth noting that the design of the gates must fulfil the rule of preserving the cross sections of the gates. In this design it was set to 0.3 mmWith regards to the second issue , the main concern is represented by the selection of optimized 3D-printing parameters in order to achieve high surface finishing and dimensional/geometrical accuracy. The third issue, the ejection of the part, is a critical aspect of the design since it can also cause the occurrence of failures. To address this issue, the designer must consider the mechanical stress arising on the mold insert during the injection molding and the required force to overcome the adhesion between molded parts and cavities. Leveraging the very low part thickness, in this work, the ejection was performed by a cylindrical pin with a diameter of 1.3 mm placed on the sprue at the center of the mold insert, thus pushing on a thicker region of the molded part and enabling a radial peeling of the parts from the cavities. This design rule also allows the overall molded part to be retained at the ejection side of the mold, preserving the ejection effectiveness. The fit between the pin ejector and the hole should be tight and the guidance into the mold holes should be high in order to not induce stress on the mold and avoid the occurrence of flashings. A maximum value of clearance of 30 μm is assumed as the limit for the referred tolerance. In addition, the wearing caused by the sliding steel ejectors can be very high since SLA material hardness is low. The main rule to improve the sliding of ejectors and avoid SLA mold breakages is the reduction of ejection force, which can be achieved by tapering the overall mold insert cavity. Since the molded part has very low thickness (100 μm), the cavity surfaces do not contribute to increasing the extraction force and can be neglected. On the contrary, the sprue and gate surfaces should have a draft angle along the extraction direction, typically higher than 1 degree. Since the ejection force is inversely proportional to the cavity surface roughness, another design rule to fulfill is to have high surface finishing of cavities. In this test case, ejector pins were not present in the cavities in order to not compromise the quality and the moldability of the parts. In fact, considering the very low thickness of the part, ejectors in the cavity would require high accuracy in assembly, and the ejection force and thrust could rip the part and, in better cases, mark the molded parts with the pin profile.The last issue (design for durability) should be addressed by analyzing the failure mechanisms affecting the AM mold inserts and particularly the 3D-printed SLA. As known by the state of the art summarized in Stereolithography (SLA) is a well-known technology capable of printing parts with high dimensional accuracy, smooth surface finishing, and high feature resolution, made with polymers with good mechanical properties. These features make this technology particularly suitable for small parts fabrication with challenging 3D shapes and geometry features with high surface quality. 3 and a light source comprising a class 1 violet laser emitting at a wavelength of 405 nm with a power of 250 mW and a spot diameter of 85 μm. The 3D printer allows a positioning resolution of 25 μm on the XY plane (layer) to be achieved, and the resolution along the z-axis can be set to 200, 100, 50, or 25 μm (layer thickness). In this work, the SLA 3D printing of the micro-mold insert was performed by means of a Form3 machine a , stiffness in the elastic range (Young’s modulus), hardness, and impact sensitivity (IZOD). In the past, thermal and mechanical properties of AM materials significantly limited the quality and endurance life of the AM molds, but recently, new materials with improved performance have been developed for these applications. In order to investigate material properties influence, the mold inserts were fabricated using two Formlabs resins: Standard Grey Resin V04 (G) and High Temperature V02 Resin (HT). The mechanical and thermal properties of these two materials are reported in x-axis as shown in The layer thickness was set to 25 μm in order to achieve the highest resolution and part accuracy. The slicer software Formlabs Preform (release v.3.3.3) was used to preprocess the part geometry (STL file) and generate supports and laser paths on layers c by propThe 3D-printed samples were washed in a Formlabs Form Wash machine for 20 min in high-purity 99.9% isopropyl alcohol (IPA) in order to remove the liquid resin on the part surfaces. All supports were removed with a cutter and finally the samples were post-processed with UV exposure performed in a Formlabs Form Cure machine and heat treatment (only HT resin after UV curing) in laboratory oven   29,30].,30.29,30z-axis resolution), and geometrical part distortion due to the peeling mechanism of the cured layer. For these reasons, the assembly of the SLA mold insert into the steel mold requires a final adjustment on mating surfaces by means of manual tools and finishing abrasive paper. In order to guarantee a satisfactory cavity filling and avoid flashings, the parallelism of matching surfaces should be verified and deviation should be limited below a tolerance target. Injection molding clamping can completely or partially compensate for a low deviation depending on the clearance fit between the mold base and the SLA mold insert. The bottom-up (inverted) SLA technology is affected by three main accuracy issues: minimum size planar feature (laser spot diameter), minimum layer thickness (N = 100 μm. The deviation Δiμ% is defined by Equation (1).The SLA mold inserts were dimensionally characterized by a confocal microscope  in order to measure the real depth of the manufactured cavities. In addition, the planarity of the insert parting surface was evaluated once the mold was assembled. For both inserts, two of the four cavities were selected , as verified by a double t-sample test. A small difference was observed along line (c), and this was mainly due to the position near the gate having a higher depth according to the design specifications. For the HT insert, the depth measurements between the two cavities were slightly different but acceptable. These results confirm the effectiveness of SLA technology in the fabrication of mold inserts with thin cavities with accurate dimensions. Finally, the planarity of the G insert was verified by measuring the differences in the height between the upper parting surface of the SLA insert and the grinded steel plate of the mold once assembled. The measurements were performed along the bisection line of the cavities   was chosen for this study. The adopted POM belongs to the family of engineering thermoplastics. It has a partially crystalline structure with a high degree of crystallization, depending on process parameters, and it presents an ideal combination of strength, stiffness, and toughness. This combination of characteristics, in association with good tribological properties, makes it very suitable for molding applications. 2 and injection volume of 150 mm3. During the process, the material, in form of granules, is transferred from a hopper into a plasticizing unit so that it becomes molten and soft. The material is then forced under pressure into a mold cavity, where it is subjected to holding pressure for a specific time to compensate for material shrinkage. After a sufficient time, the material freezes into the mold cavity, gets ejected, and the cycle is repeated.The insert, realized via SLA, was mounted on the mold base and then assembled in a micro-molding machine . It is characterized by a two-piston architecture: one for material pre-plasticizing (diameter 6 mm) and the second for injection (diameter 3 mm) . The motSeveral inserts in G resin were printed in order to screen suitable process parameters until the most favorable set  was idenAfter the time necessary to reach the thermal steady state, a short series of 30 samples was molded, evaluating both the capacity to fill the thin cavities and the capability of the SLA mold insert. An important aspect to be considered is mold wear due to the melt flow and cavity filling that occurs at high temperatures, generally around the polymer’s melting point or higher. In this experiment, the injection speed was set at 130 mm/s and the melt temperature was kept at 230 °C, as is typical for POM. It must be considered that the melt temperature is particularly critical for SLA G resin since its glass transition temperature (Tg) is about 75 °C ; thus, dThe G resin insert life was evaluated by the number of shots and, after the 30 cycles, a chipping damage occurred in the insert near the gates where a higher melt pressure was experienced a. On coniμ,30% are defined by Equation (2).Along the flow path, high temperature gradients and local melting of the skin of the mold and material removal could appear. This wearing mechanism can significantly compromise the life of the mold since it results in accuracy loss and geometry out-of-tolerance, as shown in The measured depths and calculated variation show that the cavity wear occurred in the G resin insert, whereas HT resin insert did not undergo significant variation. In particular, the increment percentage of the G insert in cavity 2 was about +21% in correspondence to all measurement sections  flashes in the gate area, probably due to the insert damage and high pressure during processing, and (ii) incomplete filling of the final part because of the melt freezing . ThroughAfter the first part of the experimentation of the manufacture of 30 samples, the HT insert was mounted again in the mold and an additional injection molding campaign was performed in order to investigate its failure mechanisms and lifetime. The same parameters reported in A further investigation was finally performed considering three levels for the injection speed  in order to evaluate the cavity filling, avoiding the flash formation around the gate. The filling lengths are reported in As illustrated in In this work, a thin cavity mold was manufactured via stereolithography and tested via injection molding in order to assess the feasibility of the SLA/µ-IM process chain. Design rules for additive manufacturing were applied in order to prevent injection molding issues and ensure a longer mold insert endurance. Two kinds of inserts were produced by SLA with different resins and were measured, showing good dimensional and thickness accuracy, with deviations from nominal values below 9%. The assembly of the insert into the base mold was instead affected by parallelism deviation due to accuracy in mechanical couplings and to the mold insert geometric tolerances. These deviations were mainly attributed to the mold insert distortion induced by the SLA peeling mechanism, as in the case of the measured planarity deviation of about 50 μm on the parting surface for the grey insert. However, the assembly issue was almost resolved using the HT resin insert. A numerical simulation was performed to assess the thermal behavior of the SLA resin insert when it replaces a steel one. The performed analysis suggested that, before molding, it is necessary to warm up the polymeric insert for 30 min.Finally, a pre-series of about 30 molding cycles was performed and, although the molded thin features were affected by some defects, the replication accuracy was quite good regarding the cavity filling. In particular, the cavity filling was investigated while considering two possible results: maximum infill accepting flashes only in the center of the insert, and maximum infill without flashes. For the first goal, the samples obtained with the grey insert presented a replicability of 92%, whereas for the HT insert it reached 98%. For the second goal, using the grey insert the samples presented an infill of 4.26 ± 0.34 mm with an injection speed of 120 mm/s, whereas with the HT insert the samples infill was reduced to 2.05 ± 0.11 mm with an injection speed of 100 mm/s. However, the apparently better performance of the G insert was probably due to the damages that increased the cavity depth, helping the filling.Regarding the mold damage, the grey insert showed wear due to the high-temperature polymer injection in the cavities, with increments of cavity depth up to 21%. This differed for the HT insert, which was still perfect after 30 molding cycles with no relevant damages measured. This material removal along the flow path was due to high temperature gradients and local melting of the skin of the mold. After 55 cycles, the HT mold insert exhibited flashes on the pin ejector caused by the wearing of the pin sliding in the molded part extraction. This failure, never reported in previous studies, is quite severe since it definitively causes the loss of the function of the molded part extraction.This research showed that micro-injection molding process using an SLA mold insert are feasible and affordable but require accuracy, especially in soft-insert fabrication, assembly, and process parameter selection to prolong the tool life. AM and, in particular, SLA, should not be conceived as a replacement for injection molding or other traditional technologies for polymers, but they do have the potential to improve them, ensuring complex and accurate molds for small batches in a quick and low-cost way.