The role of maternal gut hormones in normal pregnancy: fasting plasma active glucagon-like peptide 1 level is a negative predictor of fetal abdomen circumference and maternal weight change

Abstract

Maternal weight in pregnancy contributes to a glycemic environment that affects fetal growth. Gut peptides (glucagon-like peptide 1 (GLP1), glucose-dependent insulinotropic peptide (GIP), ghrelin, and peptide YY (PYY)) have been related to insulin sensitivity and secretion, weight control, and adipose tissue metabolism. This study aimed at examining the associations of gut hormones during pregnancy with maternal glucose homeostasis, maternal weight, and fetal growth. A total of 55 pregnant nonobese, nondiabetic Caucasian women were examined during the three trimesters of pregnancy, and anthropometric measurements, evaluation of fasting maternal plasma GLP1 (active), ghrelin (active), total PYY, total GIP, and a 75-g oral glucose tolerance test were done in them. Homeostasis model assessment (HOMA-R), insulin sensitivity index (ISI), and indices of insulin secretion were calculated. Fetal growth was estimated by ultrasound. Fasting GLP1 increased significantly from the second to the third trimester (P<0.05). Fasting GLP1 correlated positively with high-density lipoprotein cholesterol (r=0.52, P=0.04). At the second trimester, fasting GLP1 levels correlated negatively with fetal abdomen circumference (r=-0.55, P=0.034), birth weight (r=-0.50, P=0.040), HOMA-R (r=-0.65, P=0.001), insulin secretion, and triglycerides. At the first trimester, fasting ghrelin levels correlated negatively with HOMA-R and insulin secretion, and positively with ISI. In backward multiple regression analysis, the first trimester GLP1 levels were the best negative predictors of the second trimester fetal abdomen circumference (beta=-0.96, P=0.009). In longitudinal regression model, maternal fat and HOMA-R were the positive predictors of maternal weight change during pregnancy, and fasting GLP1 levels were the negative predictors of maternal weight change during pregnancy. During pregnancy, maternal GLP1 might be involved in mechanisms that compensate for the pregnancy-related increase in glycemia and insulin resistance, suggesting a role of this peptide in maternal metabolism and weight and fetal growth.