Early prediction of fetal macrosomia in diabetes mellitus.

We studied 374 pregnant diabetic women to determine the value of various ultrasound parameters in the prediction of fetal macrosomia. The correlation between ultrasonographic signs and maternal glycaemia in the development of fetal macrosomia was also studied. Significant correlation was observed between the accurence of hydramnios and future macrosomia during the second-trimester (p less than 0.001). Serum fructosamine levels as an index of maternal glycaemia in patients of macrosomic fetuses were significantly higher throughout the pregnancy as compared with mothers of infants with normal birth weight (p less than 0.001). These data suggest: 1. The presence of hydramnios in the second trimester is a useful predictor of macrosomia in diabetic patients (specificity: 86%, negative predictive value: 88%). 2. Maternal diabetic control during pregnancy has a significant influence on fetal growth and contributes to the development of fetal macrosomia. 3. The lack of correlation between the frequency of hydramnios and fructosamine levels suggests that a mechanism other than carbohydrate metabolism also plays an important role in the development of fetal macrosomia.