A 32-year-old woman with diabetes mellitus delivers a child after 38 weeks of gestation. Which of the following is the most likely abnormality that might be encountered in this child at birth?

Tight glucose control in the diabetic mother is necessary to prevent overstimulation of the fetal pancreas during gestation. Fetuses exposed to hyperglycemia in utero may develop hyperplasia of the pancreatic b-cells, which may secrete insulin autonomously and cause hypoglycemia at birth and in the early neonatal period. Infants of diabetic mothers show a 5% to 10% incidence of major development abnormalities. Increased birth weight is commonly encountered in offspring of diabetic mothers (see choice D). The incidence of mental retardation (choice E) is not specifically increased.Diagnosis: Gestational diabetes