Sex differences in DNA methylation across gestation: a large scale, cross-cohort, multi-tissue analysis.

Biological sex is a key variable influencing many physiological systems. Disease prevalence as well as treatment success can be modified by sex. Differences emerge already early in life and include pregnancy complications and adverse birth outcomes. The placenta is a critical organ for fetal development and shows sex-based differences in the expression of hormones and cytokines. Epigenetic regulation, such as DNA methylation (DNAm), may underlie the previously reported placental sexual dimorphism. We associated placental DNAm with fetal sex in three cohorts. Individual cohort results were meta-analyzed with random-effects modelling. CpG-sites differentially methylated with sex were further investigated regarding pathway enrichment, overlap with methylation quantitative trait loci (meQTLs), and hits from phenome-wide association studies (PheWAS). We evaluated the consistency of findings across tissues (CVS, i.e. chorionic villus sampling from early placenta, and cord blood) as well as with gene expression. We identified 10,320 epigenome-wide significant sex-differentially methylated probes (DMPs) spread throughout the epigenome of the placenta at birth. Most DMPs presented with lower DNAm levels in females. DMPs mapped to genes upregulated in brain, were enriched for neurodevelopmental pathways and significantly overlapped with meQTLs and PheWAS hits. Effect sizes were moderately correlated between CVS and placenta at birth, but only weakly correlated between birth placenta and cord blood. Sex differential gene expression in birth placenta was less pronounced and implicated genetic regions only marginally overlapped with those associated with differential DNAm. Our study provides an integrative perspective on sex-differential DNAm in perinatal tissues underscoring the possible link between placenta and brain.

Cooking with liquefied petroleum gas or biomass and fetal growth outcomes: a multi-country randomised controlled trial.

BACKGROUND: Household air pollution might lead to fetal growth restriction during pregnancy. We aimed to investigate whether a liquefied petroleum gas (LPG) intervention to reduce personal exposures to household air pollution during pregnancy would alter fetal growth. METHODS: The Household Air Pollution Intervention Network (HAPIN) trial was an open-label randomised controlled trial conducted in ten resource-limited settings across Guatemala, India, Peru, and Rwanda. Pregnant women aged 18-34 years (9-19 weeks of gestation) were randomly assigned in a 1:1 ratio to receive an LPG stove, continuous fuel delivery, and behavioural messaging or to continue usual cooking with biomass for 18 months. We conducted ultrasound assessments at baseline, 24-28 weeks of gestation (the first pregnancy visit), and 32-36 weeks of gestation (the second pregnancy visit), to measure fetal size; we monitored 24 h personal exposures to household air pollutants during these visits; and we weighed children at birth. We conducted intention-to-treat analyses to estimate differences in fetal size between the intervention and control group, and exposure-response analyses to identify associations between household air pollutants and fetal size. This trial is registered with ClinicalTrials.gov (NCT02944682). FINDINGS: Between May 7, 2018, and Feb 29, 2020, we randomly assigned 3200 pregnant women (1593 to the intervention group and 1607 to the control group). The mean gestational age was 14·5 (SD 3·0) weeks and mean maternal age was 25·6 (4·5) years. We obtained ultrasound assessments in 3147 (98·3%) women at baseline, 3052 (95·4%) women at the first pregnancy visit, and 2962 (92·6%) at the second pregnancy visit, through to Aug 25, 2020. Intervention adherence was high (the median proportion of days with biomass stove use was 0·0%, IQR 0·0-1·6) and pregnant women in the intervention group had lower mean exposures to particulate matter with a diameter less than 2·5 µm (PM2·5; 35·0 [SD 37·2] µg/m3vs 103·3 [97·9] µg/m3) than did women in the control group. We did not find differences in averaged post-randomisation Z scores for head circumference (0·30 vs 0·39; p=0·04), abdominal circumference (0·38 vs 0·39; p=0·99), femur length (0·44 vs 0·45; p=0·73), and estimated fetal weight or birthweight (-0·13 vs -0·12; p=0·70) between the intervention and control groups. Personal exposures to household air pollutants were not associated with fetal size. INTERPRETATION: Although an LPG cooking intervention successfully reduced personal exposure to air pollution during pregnancy, it did not affect fetal size. Our findings do not support the use of unvented liquefied petroleum gas stoves as a strategy to increase fetal growth in settings were biomass fuels are used predominantly for cooking. FUNDING: US National Institutes of Health and Bill & Melinda Gates Foundation. TRANSLATIONS: For the Kinyarwanda, Spanish and Tamil translations of the abstract see Supplementary Materials section.

Association between maternal cardiometabolic markers and fetal growth in non-complicated pregnancies: a secondary analysis of the PRINCESA cohort.

The objective of this study was to evaluate the association of maternal cardiometabolic markers trajectories (glucose, triglycerides (TG), total cholesterol, systolic blood pressure (SBP) and diastolic blood pressure (DBP)) with estimated fetal weight trajectories and birth weight in Mexican pregnant women without medical complications. Cardiometabolic marker trajectories were characterized using group-based trajectory models. Mixed-effect and linear regression models were estimated to assess the association of maternal trajectories with estimated fetal weight and birth weight. The final sample comprised 606 mother-child dyads. Two trajectory groups of maternal cardiometabolic risk indicators during pregnancy were identified (high and low). Fetuses from women with higher values of TG had higher weight gain during pregnancy ( ß ^ = 24.00 g; 95%CI: 12.9, 35.3), were heavier at the sixth month ( ß ^ =48.24 g; 95%CI: 7.2, 89.7) and had higher birth weight ( ß ^ = 89.08 g; 95%CI: 20.8, 157.4) than fetuses in the low values trajectory. Fetuses from mothers with high SBP and DBP had less weight in the sixth month of pregnancy ( ß ^ = - 42.4 g; 95%CI: - 82.7, - 2.1 and ß ^ = - 50.35 g; 95%CI: - 94.2, - 6.4), and a higher DBP trajectory was associated with lower birth weight ( ß ^ = - 101.48 g; 95%CI: - 176.5, - 26.4). In conclusion, a longitudinal exposition to high values of TG and BP was associated with potentially adverse effects on fetal growth. These findings support the potential modulation of children's phenotype by maternal cardiometabolic conditions in pregnancies without medical complications.

Developmental Windows for Effects of Choline and Folate on Excitatory and Inhibitory Neurotransmission During Human Gestation.

Choline and folate are critical nutrients for fetal brain development, but the timing of their influence during gestation has not been previously characterized. At different periods during gestation, choline stimulation of α7-nicotinic receptors facilitates conversion of γ-aminobutyric acid (GABA) receptors from excitatory to inhibitory and recruitment of GluR1-R2 receptors for faster excitatory responses to glutamate. The outcome of the fetal development of inhibition and excitation was assessed in 159 newborns by P50 cerebral auditory-evoked responses. Paired stimuli, S1, S2, were presented 500 msec apart. Higher P50 amplitude in response to S1 (P50S1microV) assesses excitation, and lower P50S2microV assesses inhibition in this paired-stimulus paradigm. Development of inhibition was related solely to maternal choline plasma concentration and folate supplementation at 16 weeks' gestation. Development of excitation was related only to maternal choline at 28 weeks. Higher maternal choline concentrations later in gestation did not compensate for earlier lower concentrations. At 4 years of age, increased behavior problems on the Child Behavior Checklist 1½-5yrs were related to both newborn inhibition and excitation. Incomplete development of inhibition and excitation associated with lower choline and folate during relatively brief periods of gestation thus has enduring effects on child development.

Oxidative Effects in Early Stages of Embryo Development Due to Alcohol Consumption.

Alcohol, a widely consumed drug, exerts significant toxic effects on the human organism. This review focuses on its impact during fetal development, when it leads to a spectrum of disorders collectively termed Fetal Alcohol Spectrum Disorders (FASD). Children afflicted by FASD exhibit distinct clinical manifestations, including facial dysmorphism, delayed growth, and neurological and behavioral disorders. These behavioral issues encompass diminished intellectual capacity, memory impairment, and heightened impulsiveness. While the precise mechanisms underlying alcohol-induced fetal damage remain incompletely understood, research indicates a pivotal role for reactive oxygen species (ROS) that are released during alcohol metabolism, inciting inflammation at the cerebral level. Ethanol metabolism amplifies the generation of oxidant molecules, inducing through alterations in enzymatic and non-enzymatic systems responsible for cellular homeostasis. Alcohol consumption disrupts endogenous enzyme activity and fosters lipid peroxidation in consumers, potentially affecting the developing fetus. Addressing this concern, administration of metformin during the prenatal period, corresponding to the third trimester of human pregnancy, emerges as a potential therapeutic intervention for mitigating FASD. This proposed approach holds promise for ameliorating the adverse effects of alcohol exposure on fetal development and warrants further investigation.

Ambient air temperature exposure and foetal size and growth in three European birth cohorts.

INTRODUCTION: Ambient air temperature may affect birth outcomes adversely, but little is known about their impact on foetal growth throughout pregnancy. We evaluated the association between temperature exposure during pregnancy and foetal size and growth in three European birth cohorts. METHODS: We studied 23,408 pregnant women from the English Born in Bradford cohort, Dutch Generation R Study, and Spanish INMA Project. Using the UrbClimTM model, weekly ambient air temperature exposure at 100x100m resolution at the mothers' residences during pregnancy was calculated. Estimated foetal weight, head circumference, and femur length at mid and late pregnancy and weight, head circumference, and length at birth were converted into standard deviation scores (SDS). Foetal growth from mid to late pregnancy was calculated (grams or centimetres/week). Cohort/region-specific distributed lag non-linear models were combined using a random-effects meta-analysis and results presented in reference to the median percentile of temperature (14 °C). RESULTS: Weekly temperatures ranged from -5.6 (Bradford) to 30.3 °C (INMA-Sabadell). Cold and heat exposure during weeks 1-28 were associated with a smaller and larger head circumference in late pregnancy, respectively (e.g., for 9.5 °C: -1.6 SDS [95 %CI -2.0; -0.4] and for 20.0 °C: 1.8 SDS [0.7; 2.9]). A susceptibility period from weeks 1-7 was identified for cold exposure and a smaller head circumference at late pregnancy. Cold exposure was associated with a slower head circumference growth from mid to late pregnancy (for 5.5 °C: -0.1 cm/week [-0.2; -0.04]), with a susceptibility period from weeks 4-12. No associations that survived multiple testing correction were found for other foetal or any birth outcomes. CONCLUSIONS: Cumulative exposure to cold and heat during pregnancy was associated with changes in foetal head circumference throughout gestation, with susceptibility periods for cold during the first pregnancy trimester. No associations were found at birth, suggesting potential recovery. Future research should replicate this study across different climatic regions including varying temperature profiles.

Application of artificial neural networks to evaluate femur development in the human fetus.

The present article concentrates on an innovative analysis that was performed to assess the development of the femur in human fetuses using artificial intelligence. As a prerequisite, linear dimensions, cross-sectional surface areas and volumes of the femoral shaft primary ossification center in 47 human fetuses aged 17-30 weeks, originating from spontaneous miscarriages and preterm deliveries, were evaluated with the use of advanced imaging techniques such as computed tomography and digital image analysis. In order to ensure the data representativeness and to avoid introducing any hidden structures that may exist in the data, the entire dataset was randomized and separated into three subsets: training (50% of cases), testing (25% of cases), and validation (25% of cases). Based on the collected numerical data, an artificial neural network was devised, trained, and subject to testing in order to synchronously estimate five parameters of the femoral shaft primary ossification center, thus leveraging fundamental information such as gestational age and femur length. The findings reveal the formulated multi-layer perceptron model denoted as MLP 2-3-2-5 to exhibit robust predictive efficacy, as evidenced by the linear correlation coefficient between actual values and network outputs: R = 0.955 for the training dataset, R = 0.942 for validation, and R = 0.953 for the testing dataset. The authors have cogently demonstrated that the use of an artificial neural network to assess the growing femur in the human fetus may be a valuable tool in prenatal tests, enabling medical doctors to quickly and precisely assess the development of the fetal femur and detect potential anatomical abnormalities.

Paternal DDT exposure induces sex-specific programming of fetal growth, placenta development and offspring's health phenotypes in a mouse model.

Mounting evidence suggests that environmentally induced epigenetic inheritance occurs in mammals and that traits in the progeny can be shaped by parental environmental experiences. Epidemiological studies link parental exposure to environmental toxicants, such as the pesticide DDT, to health phenotypes in the progeny, including low birth and increased risk of chronic diseases later in life. Here, we show that the progeny of male mice exposed to DDT in the pre-conception period are born smaller and exhibit sexual dimorphism in metabolic function, with male, but not female, offspring developing severe glucose intolerance compared to controls. These phenotypes in DDT offspring were linked to reduced fetal growth and placenta size as well as placenta-specific reduction of glycogen levels and the nutrient sensor and epigenetic regulator OGT, with more pronounced phenotypes observed in male placentas. However, placenta-specific genetic reduction of OGT only partially replicates the metabolic phenotype observed in offspring of DDT-exposed males. Our findings reveal a role for paternal pre-conception environmental experiences in shaping placenta development and in fetal growth restriction. While many questions remain, our data raise the tantalizing possibility that placenta programming could be a mediator of environmentally induced intergenerational epigenetic inheritance of phenotypes and needs to be further evaluated.

The role of metabolism in cardiac development.

Metabolism is the fundamental process that sustains life. The heart, in particular, is an organ of high energy demand, and its energy substrates have been studied for more than a century. In recent years, there has been a growing interest in understanding the role of metabolism in the early differentiation of pluripotent stem cells and in cancer research. Studies have revealed that metabolic intermediates from glycolysis and the tricarboxylic acid cycle act as co-factors for intracellular signal transduction, playing crucial roles in regulating cell behaviors. Mitochondria, as the central hub of metabolism, are also under intensive investigation regarding the regulation of their dynamics. The metabolic environment of the fetus is intricately linked to the maternal metabolic status, and the impact of the mother's nutrition and metabolic health on fetal development is significant. For instance, it is well known that maternal diabetes increases the risk of cardiac and nervous system malformations in the fetus. Another notable example is the decrease in the risk of neural tube defects when pregnant women are supplemented with folic acid. These examples highlight the profound influence of the maternal metabolic environment on the fetal organ development program. Therefore, gaining insights into the metabolic environment within developing fetal organs is critical for deepening our understanding of normal organ development. This review aims to summarize recent findings that build upon the historical recognition of the environmental and metabolic factors involved in the developing embryo.

Analyzing the impact of phthalate and DINCH exposure on fetal growth in a cohort with repeated urine collection.

BACKGROUND: Most previous studies investigating the associations between prenatal exposure to phthalates and fetal growth relied on measurements of phthalate metabolites at a single time point. They also focused on weight at birth without assessing growth over pregnancy, preventing the identification of potential periods of fetal vulnerability. We examined the associations between pregnancy urinary phthalate metabolites and fetal growth outcomes measured twice during pregnancy and at birth. METHODS: For 484 pregnant women, we assessed 13 phthalate and two 1,2-cyclohexane dicarboxylic acid, diisononyl ester (DINCH) metabolite concentrations from two within-subject weekly pools of up to 21 urine samples (median of 18 and 34 gestational weeks, respectively). Fetal biparietal diameter, femur length, head and abdominal circumferences were measured during two routine pregnancy follow-up ultrasonographies (median 22 and 32 gestational weeks, respectively) and estimated fetal weight (EFW) was calculated. Newborn weight, length, and head circumference were measured at birth. Associations between phthalate/DINCH metabolite and growth parameters were investigated using adjusted linear regression and Bayesian kernel machine regression models. RESULTS: Detection rates were above 99 % for all phthalate/DINCH metabolites. While no association was observed with birth measurements, mono-iso-butyl phthalate (MiBP) and mono-n-butyl phthalate (MnBP) were positively associated with most fetal growth parameters measured at the second trimester. Specifically, MiBP was positively associated with biparietal diameter, head and abdominal circumferences, while MnBP was positively associated with EFW, head and abdominal circumferences, with stronger associations among males. Pregnancy MnBP was positively associated with biparietal diameter and femur length at third trimester. Mixture of phthalate/DINCH metabolites was positively associated with EFW at second trimester. CONCLUSIONS: In this pregnancy cohort using repeated urine samples to assess exposure, MiBP and MnBP were associated with increased fetal growth parameters. Further investigation on the effects of phthalates on child health would be relevant for expanding current knowledge on their long-term effects.

Epigenetic modifications in the ferroptosis pathway in cord blood cells from newborns of smoking mothers and their influence on fetal growth.

Maternal smoking during pregnancy increases oxidative stress and decreases antioxidant capacity in newborns. Uncontrolled oxidative stress plays a role in fetal development disorders and in adverse perinatal outcomes. In order to identify molecular pathways involved in low fetal growth, epigenetic modifications in newborns of smoking and non-smoking mothers were examined. Low birth weight newborns of mothers who smoked more than 10 cigarettes per day during the first trimester of pregnancy and normal birth weight newborns of mothers who did not smoke during pregnancy were included in the study. DNA was extracted from umbilical cord blood of term newborns. 125 differentially methylated regions were identified by MeDIP-Seq. Functional analysis revealed several pathways, such as ferroptosis, that were enriched in differentially methylated genes after prenatal smoke exposure. GPX4 and PCBP1 were found to be hypermethylated and associated with low fetal growth. These epigenetic modifications in ferroptosis pathway genes in newborns of smoking mothers can potentially contribute to intrauterine growth restriction through the induction of cell death via lipid peroxidation of cell membranes. The identification of epigenetic modifications in the ferroptosis pathway sheds light on the potential mechanisms underlying the pathophysiology of low birth weight in infants born to smoking mothers.

Pre-pregnancy body mass index, gestational diabetes mellitus, and gestational weight gain: individual and combined effects on fetal growth.

Background: Pre-pregnancy body mass index (BMI), gestational diabetes mellitus (GDM), and gestational weight gain (GWG) are interlinked and may play a complex role in fetal growth. We aimed to examine the relationship between pre-pregnancy BMI, GDM, GWG, and fetal growth outcomes and explore the contribution of GDM and GWG to the relationship between Pre-pregnancy obesity/overweight and large-for-gestational-age (LGA) in a prospective cohort. Methods: We prospectively recruited women in the first trimester and having one-step GDM screened with a 75-g oral glucose tolerance test between 24 and 28 weeks of gestation (n = 802). Outcomes included LGA, small-for-gestational-age (SGA), and preterm birth. To assess the individual and cumulative associations between pre-pregnancy BMI, GDM, GWG, and these outcomes, we used multivariate logistic regression analysis. Furthermore, we employed structural equation modeling (SEM) to investigate the mediating role of GDM and excessive GWG in the correlation between pre-pregnancy overweight/obesity and LGA. Results: Pre-pregnancy obesity, GDM, and excessive GWG were all independently associated with increased odds of LGA. Inadequate GWG was associated with higher odds of preterm birth. Compared with women unexposed to pre-pregnancy overweight/obesity, GDM, or excessive GWG, women exposed any two conditions had higher odds for LGA (AOR 3.18, 95% CI 1.25-8.11) and women with coexistence of all had the highest odds for LGA (AOR 8.09, 95% CI 2.18-29.97). The mediation analysis showed that GDM explained 18.60% (p < 0.05) of the total effect of pre-pregnancy overweight/obesity on LGA, and GWG explained 17.44% (p < 0.05) of the total effect. Conclusion: Pre-pregnancy obesity/overweight, GDM, and excessive GWG are associated with higher odds of fetal growth disturbances as individual factors and when they co-exist. The effect of pre-pregnancy overweight/obesity on LGA is partially achieved through GDM and excessive GWG.

Sex and fetal genome influence gene expression in pig endometrium at the end of gestation.

BACKGROUND: A fine balance of feto-maternal resource allocation is required to support pregnancy, which depends on interactions between maternal and fetal genetic potential, maternal nutrition and environment, endometrial and placental functions. In particular, some imprinted genes have a role in regulating maternal-fetal nutrient exchange, but few have been documented in the endometrium. The aim of this study is to describe the expression of 42 genes, with parental expression, in the endometrium comparing two extreme breeds: Large White (LW); Meishan (MS) with contrasting neonatal mortality and maturity at two days of gestation (D90-D110). We investigated their potential contribution to fetal maturation exploring genes-fetal phenotypes relationships. Last, we hypothesized that the fetal genome and sex influence their endometrial expression. For this purpose, pure and reciprocally crossbred fetuses were produced using LW and MS breeds. Thus, in the same uterus, endometrial samples were associated with its purebred or crossbred fetuses. RESULTS: Among the 22 differentially expressed genes (DEGs), 14 DEGs were differentially regulated between the two days of gestation. More gestational changes were described in LW (11 DEGs) than in MS (2 DEGs). Nine DEGs were differentially regulated between the two extreme breeds, highlighting differences in the regulation of endometrial angiogenesis, nutrient transport and energy metabolism. We identified DEGs that showed high correlations with indicators of fetal maturation, such as ponderal index at D90 and fetal blood fructose level and placental weight at D110. We pointed out for the first time the influence of fetal sex and genome on endometrial expression at D90, highlighting AMPD3, CITED1 and H19 genes. We demonstrated that fetal sex affects the expression of five imprinted genes in LW endometrium. Fetal genome influenced the expression of four genes in LW endometrium but not in MS endometrium. Interestingly, both fetal sex and fetal genome interact to influence endometrial gene expression. CONCLUSIONS: These data provide evidence for some sexual dimorphism in the pregnant endometrium and for the contribution of the fetal genome to feto-maternal interactions at the end of gestation. They suggest that the paternal genome may contribute significantly to piglet survival, especially in crossbreeding production systems.

Improved estimation of the relationship between fetal growth and late stillbirth in the United States, 2014-15.

In the United States the rate of stillbirth after 28 weeks' gestation (late stillbirth) is 2.7/1000 births. Fetuses that are small for gestational age (SGA) or large for gestational age (LGA) are at increased risk of stillbirth. SGA and LGA are often categorized as growth or birthweight ≤ 10th and ≥ 90th centile, respectively; however, these cut-offs are arbitrary. We sought to characterize the relationship between birthweight and stillbirth risk in greater detail. Data on singleton births between 28- and 44-weeks' gestation from 2014 to 2015 were extracted from the US Centers for Disease Control and Prevention live birth and fetal death files. Growth was assessed using customized birthweight centiles (Gestation Related Optimal Weight; GROW). The analyses included logistic regression using SGA/LGA categories and a generalized additive model (GAM) using birthweight centile as a continuous exposure. Although the SGA and LGA categories identified infants at risk of stillbirth, categorical models provided poor fits to the data within the high-risk bins, and in particular markedly underestimated the risk for the extreme centiles. For example, for fetuses in the lowest GROW centile, the observed rate was 39.8/1000 births compared with a predicted rate of 11.7/1000 from the category-based analysis. In contrast, the model-predicted risk from the GAM tracked closely with the observed risk, with the GAM providing an accurate characterization of stillbirth risk across the entire birthweight continuum. This study provides stillbirth risk estimates for each GROW centile, which clinicians can use in conjunction with other clinical details to guide obstetric management.

Independent and Combined Effects of Prenatal Alcohol Exposure and Prenatal Stress on Fetal HPA Axis Development.

Prenatal alcohol exposure (PAE) and prenatal stress (PS) are highly prevalent conditions known to affect fetal programming of the hypothalamic-pituitary-adrenal (HPA) axis. The objectives of this study were to assess the effect of light PAE, PS, and PAE-PS interaction on fetal HPA axis activity assessed via placental and umbilical cord blood biomarkers. Participants of the ENRICH-2 cohort were recruited during the second trimester and classified into the PAE and unexposed control groups. PS was assessed by the Perceived Stress Scale. Placental tissue was collected promptly after delivery; gene and protein analysis for 11ß-HSD1, 11ß-HSD2, and pCRH were conducted by qPCR and ELISA, respectively. Umbilical cord blood was analyzed for cortisone and cortisol. Pearson correlation and multivariable linear regression examined the association of PAE and PS with HPA axis biomarkers. Mean alcohol consumption in the PAE group was ~2 drinks/week. Higher PS was observed in the PAE group (p < 0.01). In multivariable modeling, PS was associated with pCRH gene expression (ß = 0.006, p < 0.01), while PAE was associated with 11ß-HSD2 protein expression (ß = 0.56, p < 0.01). A significant alcohol-by-stress interaction was observed with respect to 11ß-HSD2 protein expression (p < 0.01). Results indicate that PAE and PS may independently and in combination affect fetal programming of the HPA axis.

Single and combined exposures to bisphenol A and benzophenone-3 during early mouse pregnancy have differential effects on fetal and placental development.

Endocrine disrupting chemicals (EDCs) possess the capability to interfere with the endocrine system by binding to hormone receptors, for example on immune cells. Specific effects have already been described for individual substances, but the impact of exposure to chemical mixtures during pregnancy on maternal immune regulation, placentation and fetal development is not known. In this study, we aimed to investigate the combined effects of two widespread EDCs, bisphenol A (BPA) and benzophenone-3 (BP-3), at allowed concentrations on crucial pregnancy processes such as implantation, placentation, uterine immune cell populations and fetal growth. From gestation day (gd) 0 to gd10, female mice were exposed to 4 µg/kg/d BPA, 50 mg/kg/d BP-3 or a BPA/BP-3 mixture. High frequency ultrasound and Doppler measurements were used to determine intrauterine fetal development and hemodynamic parameters. Furthermore, uterine spiral artery remodeling and placental mRNA expression were studied via histology and CHIP-RT-PCR, respectively. Effects of EDC exposure on multiple uterine immune cell populations were investigated using flow cytometry. We found that exposure to BP-3 caused intrauterine growth restriction in offspring at gd14, while BPA and BPA/BP-3 mixture caused varying effects. Moreover, placental morphology at gd12 and placental efficiency at gd14 were altered upon BP-3 exposure. Placental gene transcription was altered particularly in female offspring after in utero exposure to BP-3. Flow cytometry analyses revealed an increase in uterine T cells and NK cells in BPA and BPA/BP-3-treated dams at gd14. Doppler measurements revealed no effect on uterine hemodynamic parameters and spiral artery remodeling was not affected following EDC exposure. Our results provide evidence that exposure to BPA and BP-3 during early gestation affects fetal development in a sex-dependent manner, placental function and immune cell frequencies at the feto-maternal interface. These results call for inclusion of studies addressing pregnancy in the risk assessment of environmental chemicals.

Gestational exposure to PM2.5 disrupts fetal development by suppressing placental trophoblast syncytialization via progranulin/mTOR signaling.

Recent epidemiological and animal studies have indicated that ambient fine particulate matter (PM2.5) exposure during pregnancy is closely associated with intrauterine growth restriction (IUGR). However, the underlying mechanisms remain to be revealed. In this study, we found that gestational exposure to PM2.5 significantly decreased fetal weight and crown-rump length in mice, accompanied by insufficient placental trophoblast syncytialization and increased expression of progranulin (PGRN) in mice placenta. Administering PGRN neutralizing antibody to pregnant mice alleviated growth restriction and insufficient placental trophoblast syncytialization caused by PM2.5, accompanied with suppressed activation of the mTOR signaling pathway. Furthermore, in vitro experiments using human placental BeWo cells showed that 10 µg·mL-1 PM2.5 activated PGRN/mTOR signaling and suppressed forskolin-induced cell fusion, which was blocked by knockdown of PGRN. Taken together, our results demonstrated that PM2.5 exposure during pregnancy inhibited placental trophoblast syncytialization by activating PGRN/mTOR signaling, leading to abnormal placental development and IUGR. This study reveals a novel mechanism underlying the developmental toxicity of PM2.5 exposure during pregnancy.

RISING STARS: Bumps and bacteria: influence of the maternal microbiota on pregnancy outcomes.

During pregnancy, all major physiological systems undergo remarkable changes, driven largely by alterations in the maternal hormonal milieu. In healthy pregnancies, maternal cardiovascular and metabolic adaptation to pregnancy occurs to support fetal growth and maternal well-being. Impaired maternal adaptation to pregnancy is associated with a range of pregnancy complications, including gestational diabetes and preeclampsia. There is growing recognition of the importance of different maternal microbiota, including in the gut, vagina and oral cavity, in supporting normal maternal adaptations to pregnancy as well as evidence for microbial disturbances associating with pregnancy pathologies. Here, we aim to summarise emerging evidence demonstrating that differences in maternal microbiota associate with pregnancy outcomes and discuss potential therapeutic approaches under development that might restore an 'optimal' microbiome. In particular, we highlight recent work by ourselves and others exploring the role of the oral microbiome in pregnancy, given established links between poor oral health (e.g. periodontitis) and adverse pregnancy outcomes. Our research has focussed on specific nitrate-reducing oral bacteria which play a role in the generation of nitric oxide (NO) and other bioactive nitrogen oxides associated with cardiovascular health and maternal cardiovascular adaption to pregnancy. Ongoing research aims to define whether altered microbial profiles have clinical utility in the prediction of pregnancy pathologies, and whether interventions designed to optimise specific maternal microbiota could help prevent future complications.

Maternal exposure to particulate matter from duck houses restricts fetal growth due to inflammatory damage and oxidative stress.

The composition of particulate matter (PM) in poultry farms differs significantly from that of atmospheric PM as there is a higher concentration of microbes on farms. To assess the health effects of PM from poultry farms on pregnant animals, we collected PM from duck houses using a particulate sampler, processed it via centrifugation and vacuum concentration, and subsequently exposed the mice to airborne PM at 0.48 mg/m3 (i.e., low concentration group) and 1.92 mg/m3 (i.e., high concentration group) on the fifth day of pregnancy. After exposure until the twentieth day of pregnancy or spontaneous delivery, mice were euthanized for sampling. The effects of PM from duck houses on the pregnancy toxicity of mice were analyzed using histopathological analysis, enzyme-linked immunosorbent assay, and quantitative real-time polymerase chain reaction (qPCR). The results showed that exposure to PM had adverse effects on pregnant mice that reduced their feed intake in both groups. Microscopic lesions were observed in the lungs and placentas of pregnant mice, and the lesions worsened with increased PM concentrations, as shown by alveolar wall thickening, the infiltration of inflammatory cells in pulmonary interstitium, congestion, edema, and cellular degeneration of placenta. In pregnant mice in the high concentration group, exposure to PM significantly increased the expression of inflammatory cytokines in the lungs and placentas, caused oxidative stress, and decreased estrogen level in the blood. Exposure to PM also resulted in the reduced litter sizes of pregnant mice and shorter body and tail lengths in the fetuses delivered. Beyond that, exposure to PM significantly downregulated the levels of antioxidant factor superoxide dismutase and neurotrophic factor Ngf in the brains of fetuses. Collectively, exposure to a high concentration of PM by inhalation among pregnant mice caused significant pregnancy toxicity that led to abnormal fetal development due to inflammatory damage and oxidative stress. These findings established a foundation for future studies on the underlying mechanisms of pregnancy toxicity induced by exposure to PM.