Association of dietary fiber, liquid intake and lifestyle characteristics with gastrointestinal symptoms and pregnancy outcome

Objectives

Heartburn and constipation are common gastrointestinal symptoms during pregnancy. High fiber and liquid intake have beneficial effects on these symptoms in non- pregnant population. Our aim was to evaluate the association of dietary fiber, fluid intake and lifestyle characteristics with constipation, heartburn, and pregnancy outcome.

Study design

Two hundred pregnant women were enrolled in this prospective cohort study during the 1st trimester of pregnancy. Participants completed a self- administered questionnaire concerning bowel symptoms, dietary fiber, liquid intake, and lifestyle characteristics before pregnancy, during pregnancy and post-partum. After exclusions 173 pregnant women participated the study and 173, 173, 136, 109 and 91 completed pre-pregnancy, and 1st, 2nd, and 3rd trimester, and post-partum questionnaires, respectively. Data on deliveries and perinatal outcome (n = 173) were collected from hospital records. In trajectory analysis, the women were clustered in groups based on the intake of fiber and liquids. Generalized linear mixed models and logistic regression analyses were used to find associations of fiber and fluid intake with constipation, heartburn and pregnancy outcome.

Results and conclusions

Heartburn increased significantly during pregnancy and the highest prevalence (33%) was during the third trimester. A combination of low fiber and low fluid intake increased the risk of constipation during pregnancy (OR 5.9, 95% CI 2.00-17.4). Low fiber intake increased the risk of combined adverse outcome (cesarean section, premature delivery and/or small for gestational age; OR 3.4, 95% CI 1.2-9.6). Sufficient fiber and liquid intake may be protective against pregnancy-associated constipation and may be associated with improved pregnancy outcome.

Mendelian randomization supports causality between maternal hyperglycemia and epigenetic regulation of leptin gene in newborns

Leptin is an adipokine that acts in the central nervous system and regulates energy balance. Animal models and human observational studies have suggested that leptin surge in the perinatal period has a critical role in programming long-term risk of obesity. In utero exposure to maternal hyperglycemia has been associated with increased risk of obesity later in life. Epigenetic mechanisms are suspected to be involved in fetal programming of long term metabolic diseases. We investigated whether DNA methylation levels near LEP locus mediate the relation between maternal glycemia and neonatal leptin levels using the 2-step epigenetic Mendelian randomization approach. We used data and samples from up to 485 mother-child dyads from Gen3G, a large prospective population-based cohort. First, we built a genetic risk score to capture maternal glycemia based on 10 known glycemic genetic variants (GRS10) and showed it was an adequate instrumental variable (β = 0.046 mmol/L of maternal fasting glucose per additional risk allele; SE = 0.007; P = 7.8 × 10(-11); N = 467). A higher GRS10 was associated with lower methylation levels at cg12083122 located near LEP (β = -0.072 unit per additional risk allele; SE = 0.04; P = 0.05; N = 166). Direction and effect size of association between the instrumental variable GRS10 and methylation at cg12083122 were consistent with the negative association we observed using measured maternal glycemia. Lower DNA methylation levels at cg12083122 were associated with higher cord blood leptin levels (β = -0.17 log of cord blood leptin per unit; SE = 0.07; P = 0.01; N = 170). Our study supports that maternal glycemia is part of causal pathways influencing offspring leptin epigenetic regulation.