Effect of different maternal metabolic characteristics on fetal growth in women with gestational diabetes mellitus

Fetal growth in diabetic pregnancies is a complex process and probably abnormalities in other metabolic pathways such as protein and lipid, as well as carbohydrate are responsible for delivering of macrosomic newborn.

The purpose of this study was to investigate the association between fetal growth and different maternal metabolic parameters in women with gestational diabetes mellitus (GDM) in comparison to control group.

This was a prospective cohort study conducted between March 2011 and May 2012, on 112 pregnant women with GDM and 159 healthy pregnant women. In order to determine of lipids or lipoproteins changes during pregnancy and to investigate any possible effects on fetal growth, lipid components, glucose and insulin levels were obtained in maternal serum three times in third trimester.

Maternal serum glucose, total cholesterol (TC), low and high density lipoprotein (LDL-c, HDL-c) levels did not show any significant difference between two groups. While insulin, homeostasis model assessment-insulin resistance (HOMA-IR) and triglyceride (TG) values were detected to be significantly higher in the GDM cases especially after 32 weeks of gestation (p<0.001). After adjustment for confounding variables, maternal hypertriglyceridemia remained as a significant risk factor for delivering large for gestational age (LGA) newborns (p=0.04); and according to spearman test the increase of TG level was correlated with increase of insulin resistance and HOMA-IR (p<0.001, CI: 0.312).

Due to positive correlation of hypertriglyceridemia and hyperinsulinemia with newborn weight, it is possible to assume that elevated TGs levels in GDM cases is a reflection of variation in maternal insulin levels.