Magnetic resonance imaging in pregnancies complicated by gestational diabetes predicts infant birthweight ratio and neonatal morbidity.

The use of magnetic resonance imaging (MRI) has been shown to be safe during pregnancy and can accurately assess fetal fat and rate of growth. The purpose of this study was to investigate with MRI the relationship between maternal weight, fat distribution, and glucose levels and neonatal birthweight ratio, percent fat, and infant outcome in pregnancies complicated by gestational diabetes. Twenty gestational diabetic women were studied at 36 to 38 weeks' gestation with hemoglobin A1c, a glucose tolerance test and maternal body fat by electrical impedance. MRI scans of the maternal upper arm and from her zyphoid process to her pubic symphysis, including all fetal components, were analyzed for percent fat of the mother's arm and trunk and her fetus' trunk. All variables were then related to infant outcome (birthweight, birthweight ratio, and neonatal morbidity). Maternal body composition was related to maternal weight (p = 0.012, r = 0.54), as was maternal arm fat (p < 0.005, r = 0.60). Arm fat did correlate with trunk fat, but trunk fat did not correlate was well with weight (p = NS). Although maternal Hb A1c correlated with maternal weight (p = 0.05, r = 0.43), it did not correlate with infant birthweight. In contrast, maternal mean glucose levels correlated with both maternal and infant weight and infant birthweight ratio (p = 0.05, r = 0.60; p = 0.05, r = 0.42; and p = 0.01, r = 0.64, respectively).(ABSTRACT TRUNCATED AT 250 WORDS)