Gestational diabetes mellitus (GDM) is associated with increased maternal insulin resistance. Maternal hyperglycemia is a well known risk factor for fetal overgrowth. However, despite improved glycemia control, macrosomia complicates a significant proportion of diabetic pregnancies, resulting in increased perinatal risk. The aim of our retrospective study was to investigate the association between fetal growth and different maternal metabolic characteristics in women with GDM. The study group included 357 women (singleton pregnancy, and GDM diagnosed following WHO criteria). The following parameters were studied: maternal pre-pregnancy BMI, 75 g OGTT results, HbA(1c), triglycerides (TAG), total, HDL- and LDL-cholesterol levels at admission. Neonatal birth weight and the prevalence of being large for gestational age birth weight (LGA) was an end-point. We found a significant association between birth weight and HbA(1c), TAG, fasting OGTT glycemia, BMI and a birth weight of a large child born previously. BMI and birth weight of a large child was the strongest independent predictors for LGA. A significant increase in birth weight and the prevalence of LGA (from 10.5% to 83.3%) was related to a number of altered maternal metabolic features.
Conclusions: Fetal growth in a diabetic pregnancy is a complex process and maternal metabolic parameters other than glucose levels should be addressed to reduce the risk of macrosomia in these groups of patients.