Maternal Obesity Affects the Glucose-Insulin Axis During the First Trimester of Human Pregnancy
Julia Bandres‐Meriz, Anna M. Dieberger, Denise Hoch, Caroline Pöchlauer, Martina Bachbauer, Ariella Glasner, Tobias Niedrist, Mireille N. M. van Poppel, Gernot Desoyé
Abstract
Background and objective: The maternal glucose-insulin axis is central for metabolic adaptations required for a healthy pregnancy. Metabolic changes in obese mothers in early pregnancy have been scantly described. Here we characterized the glucose-insulin axis in the first trimester of human pregnancy and assessed the effect of maternal obesity and fat mass. Methods: Maternal blood samples (n=323) were collected during voluntary pregnancy termination (gestational age 4+0 - 11+6 weeks) after overnight fasting. Smokers (n=198) were identified by self-report and serum cotinine levels (ELISA). Maternal BMI (kg/m2) and serum leptin (ELISA) were used as proxy measures of obesity and maternal fat mass, respectively. ISHOMA insulin sensitivity index was calculated from glucose and C-peptide (ELISA) serum concentrations. Results: Glucose and C-peptide levels decreased (P < 0.001) between weeks 4-6 and 7-9, paralleled by an increase (P < 0.001) in insulin sensitivity. Glucose levels were not significantly different between BMI or leptin categories. In contrast, compared to the normal-weight /low fat mass group, C-peptide was higher in the obese (OR 1.66, CI 1.42-1.93; P < 0.001) and high fat mass group (OR 1.25, CI 1.13-1.33; P <0.001) whereas ISHOMA was lower (OR 0.57, CI 0.48-0.68; P <0.001 and OR 0.67, CI 0.60-0.76; P <0.001) respectively. Conclusions: Glucose, C-peptide and insulin sensitivity dynamically change in the first trimester of human pregnancy. Maternal obesity is associated with higher C-peptide and lower insulin sensitivity at all stages, while glucose is unaltered. These findings have implications for the timing of early gestational diabetes mellitus risk screening.