Hyperinsulinemia in Macrosomic Infants of Nondiabetic Mothers

Abstract

Objective— We tested the hypothesis that macrosomic infants of nondiabetic mothers are more likely to have hyperinsulinemia and increased subcutaneous fat. Research Design and Methods— Plasma insulin concentrations were measured in cord blood from 50 macrosomic infants and 32 normal-sized (control), term infants. All mothers had had a normal 50-g 1-h GCT. Skin-fold measurements of the triceps and subscapular area were done on 44 macrosomic infants with a Halpern caliper. Results— No difference was observed in GCT between mothers of macrosomic (5.8 ± 1.0 mM) and normal (5.7 mM) infants. The insulin level in macrosomic infants (18.75 ± 19.08 μU/ml) was significantly higher than in control infants (8.67 ± 6.64 μU/ml). Macrosomia was a predictor of hyperinsulinemia and vice versa (R2 = 0.26). Maternal height, prepregnancy weight, and weight gain were predictors for macrosomia (R2 = 0.26). No differences were noted in anthropometric measurements between hyperinsulinemic and normoinsulinemic infants. Conclusions— A subset of macrosomic infants have hyperinsulinemia. Maternal anthropometric factors as well as hyperinsulinemia are correlated with macrosomia. The macrosomia may be causally related to the high insulin levels.