Maternal lipids as strong determinants of fetal environment and growth in pregnancies with gestational Diabetes mellitus

Aim: To determine the potential contribution of maternal glucose and lipids to intrauterine metabolic environment and fetal growth in pregnancies with gestational diabetes(GDM).

Methods: In 150 pregnancies, serum trigylcerides(TG), cholesterol, free fatty acids(FFA), glycerol, insulin and glucose were determined in maternal serum during 3rd trimester and cord blood. Maternal glucose values came from the oGTT and glucose profiles. Measurements of the fetal abdominal circumference(AC) were performed simultaneously with maternal blood sampling and birth weight, BMI and neonatal fat mass were obtained past delivery.

Results: Maternal TG and FFA correlated significantly with fetal AC size (at 28 weeks: TG:p=0.001; FFA:p=0.02) and at delivery with all anthropometric measures of newborns (for FFA: birth weight:p=0.002; BMI:p=0.001; fat mass:p=0.01). After adjustment for confounding variables maternal FFA and TG at delivery remained as the only parameters independently related to LGA (p=0.008, p=0.04). Maternal FFA levels were significantly higher in those with LGA than AGA newborns (362.8+101.7 vs. 252.4+10.1, p=0.002). Maternal levels of TG, FFA, and glycerol at delivery correlated signifantly with those in cord blood (p=0.003;p=0.004;p=0.005). Fetal TG and cholesterol levels were significantly negatively correlated with newborn birth weight (p=0.001), BMI (p=0.004;) and fat mass (p=0.001). TG were significantly higher in SGA compared to AGA or LGA newborns while insulin/glucose ratio and FFA were the highest in LGA.

Conclusion: In well controlled GDM pregnancies, maternal lipids are strong predictors for fetal lipids and fetal growth. Infants with abnormal growth seem to be exposed to a distinct intrauterine environment compared to those with appropriate growth.