Project description:BackgroundIron is critical for maternal and fetal health; however, the effect of iron nutrition on fetal intrauterine growth remains unclear. This study aimed to investigate the associations of maternal iron nutrition during pregnancy with fetal intrauterine growth parameters among the Chinese population.MethodsThis retrospective birth cohort study included 482 pregnant women. Maternal information was collected by standard questionnaires. Maternal concentrations of serum ferritin and hemoglobin were detected. Fetal ultrasound examinations in the second and third trimesters were conducted. Quantile regression or linear regression models were applied to assess the associations.ResultsParticipants took iron supplementation in early, mid, and late pregnancy accounted for 19.1%, 40.3%, and 37.8%, respectively. Iron supplementation in the first and second trimesters and total iron intake in pregnancy were positively associated with fetal intrauterine growth parameters at some percentiles. Compared with those without iron supplementation in the second trimester, women with iron supplementation in the second trimester had 0.37 (95%CI = 0.24-0.49), 0.37 (95%CI = 0.26-0.48), 0.15 (95%CI = 0.04-0.26), and 0.52 (95%CI = 0.42-0.61) higher z-scores in fetal biparietal diameter, femur length, abdominal circumference, and estimated fetal weight at the 50th percentile in the second trimester, respectively. Maternal serum ferritin and hemoglobin concentrations in the first and second trimesters were positively correlated with several fetal growth parameters.ConclusionsFetal intrauterine growth may benefit from maternal iron nutrition in the first and second trimesters.
Project description:BackgroundSingle nucleotide polymorphisms (SNPs) may influence arsenic methylation efficiency, affecting arsenic metabolism. Whether gene-environment interactions affect arsenic metabolism during pregnancy remains unclear, which may have implications for pregnancy outcomes.ObjectiveWe aimed to investigate main effects as well as potential SNP-arsenic interactions on arsenic methylation efficiency in pregnant women.MethodWe recruited 1613 pregnant women in Bangladesh, and collected two urine samples from each participant, one at 4-16 weeks, and the second at 21-37 weeks of pregnancy. We determined the proportions of each arsenic metabolite [inorganic As (iAs)%, monomethylarsonic acid (MMA)%, and dimethylarsinic acid (DMA)%] from the total urinary arsenic level of each sample. A panel of 63 candidate SNPs was selected for genotyping based on their reported associations with arsenic metabolism (including in As3MT, N6AMT1, and GSTO2 genes). We used linear regression models to assess the association between each SNP and DMA% with an additive allelic assumption, as well as SNP-arsenic interaction on DMA%. These analyses were performed separately for two urine collection time-points to capture differences in susceptibility to arsenic toxicity.ResultIntron variants for As3MT were associated with DMA%. rs9527 (β = -2.98%, PFDR = 0.008) and rs1046778 (β = 1.64%, PFDR = 0.008) were associated with this measure in the early gestational period; rs3740393 (β = 2.54%, PFDR = 0.002) and rs1046778 (β = 1.97%, PFDR = 0.003) in the mid-to-late gestational period. Further, As3MT, GSTO2, and N6AMT1 polymorphisms showed different effect sizes on DMA% conditional on arsenic exposure levels. However, SNP-arsenic interactions were not statistically significant after adjusting for false discovery rate (FDR). rs1048546 in N6AMT1 had the highest significance level in the SNP-arsenic interaction test during mid-to-late gestation (β = -1.8% vs. 1.4%, PGxE_FDR = 0.075). Finally, As3MT and As3MT/CNNM2 haplotypes were associated with DMA% at both time points.ConclusionWe found that not all genetic associations reported in arsenic methylation efficiency replicate in pregnant women. Arsenic exposure level has a limited effect in modifying the association between genetic variation and arsenic methylation efficiency.
Project description:To assess whether associations between maternal smoking during pregnancy and offspring smoking initiation are due to intrauterine mechanisms.Comparison of associations of maternal and partner smoking behaviour during pregnancy with offspring smoking initiation using partner smoking as a negative control (n?=?6484) and a Mendelian randomization analysis (n?=?1020), using a genetic variant in the mothers as a proxy for smoking cessation during pregnancy.A longitudinal birth cohort in South West England.Participants of the Avon Longitudinal Study of Parents and Children (ALSPAC).Smoking status during pregnancy was self-reported by mother and partner in questionnaires administered at pregnancy. Latent classes of offspring smoking initiation (non-smokers, experimenters, late-onset regular smokers and early-onset regular smokers) were previously developed from questionnaires administered at 14-16 years. A genetic variant, rs1051730, was genotyped in the mothers.Both mother and partner smoking were similarly positively associated with offspring smoking initiation classes, even after adjustment for confounders. Odds ratios (OR) [95% confidence interval (CI)] for class membership compared with non-smokers were: experimenters: mother OR?=?1.33 (95% CI?=?1.06, 1.67), partner OR?=?1.28 (95% CI?=?1.06, 1.55), late-onset regular smokers: mother OR?=?1.80 (95% CI?=?1.43, 2.26), partner OR?=?1.86 (95% CI?=?1.52, 2.28) and early-onset regular smokers: mother OR?=?2.89 (95% CI?=?2.12, 3.94), partner OR?=?2.50 (95% CI?=?1.85, 3.37). There was no clear evidence for a dose-response effect of either mother or partner smoking heaviness on class membership. Maternal rs1051730 genotype was not clearly associated with offspring smoking initiation class in pre-pregnancy smokers (P?=?0.35).The association between smoking during pregnancy and offspring smoking initiation does not appear to operate through intrauterine mechanisms.
Project description:AimInvestigate associations of leisure time physical activity (LTPA) with DNA methylation and miRNAs during pregnancy. Patients & methods: LTPA, candidate DNA methylation and circulating miRNAs were measured (average 15 weeks gestation) in pregnant women (n = 92).ResultsEach additional hour of prepregnancy LTPA duration was associated with hypermethylation in C1orf212 (β = 0.137, 95% CI: 0.004-0.270) and higher circulating miR-146b-5p (β = 0.084, 95% CI: 0.017-0.151). Each additional metabolic equivalent hour of early-pregnancy LTPA energy expenditure was associated with higher circulating miR-21-3p (β = 0.431, 95% CI: 0.089-0.772) in women carrying female offspring, and lower circulating miR-146b-5p (β = -0.285, 95% CI: -0.528 to -0.043) and miR-517-5p (β = -0.406, 95% CI: -0.736 to -0.076) in women carrying male offspring.ConclusionOur findings suggest that LTPA may influence maternal epigenetic biomarkers, possibly in an offspring sex-specific manner.
Project description:OBJECTIVE:Case control studies suggest a relationship between maternal stress during pregnancy and childhood ADHD. However, maternal smoking, parenting style and parental psychiatric disorder are possible confounding factors. Our objective was to control for these factors by using an intra-familial design, and investigate gene-environment interactions. METHODS:One hundred forty two children, ages 6 to 12, (71 with ADHD, and their 71 non-ADHD siblings) participated in the intra-familial study design. A larger sample of ADHD children (N=305) was genotyped for DAT1 and DRD4 to examine gene-environment interactions. Symptom severity was evaluated using the Child Behavior Checklist (CBCL) and the Conners' Global Index for Parents (CGI-P). The Kinney Medical and Gynecological Questionnaire was used to report stressful events during pregnancies. RESULTS:LOGISTIC REGRESSION INDICATED THAT MOTHERS WERE MORE LIKELY TO HAVE EXPERIENCED HIGH STRESS DURING PREGNANCY OF THEIR ADHD CHILD COMPARED TO THAT OF THE UNAFFECTED SIBLING (OR: 6.3, p=.01). In the larger sample, DRD4 7/7 genotype was associated with increased symptom severity in the high stress pregnancy (p=.01). CONCLUSIONS:Maternal stress during pregnancy was associated with the development of ADHD symptomatology after controlling for family history of ADHD and other environmental factors. This association could partly be mediated through the DRD4 genotype.