A 31-year-old woman at 32 weeks gestation with gestational diabetes mellitus on medical nutrition therapy has a fetal ultrasound showing estimated fetal weight at the 95th percentile and abdominal circumference at the 97th percentile. Amniotic fluid index is normal. Which neonatal complication is this fetus at highest risk for if glucose is not optimized before delivery?

• A Neonatal hyperglycemia due to fetal pancreatic beta-cell atrophy
• B Neonatal polycythemia due to fetal hypoxia from placental insufficiency
• C Neonatal hypoglycemia due to fetal hyperinsulinemia secondary to maternal hyperglycemia ✓
• D Neonatal hypocalcemia due to maternal vitamin D deficiency

Explanation

Maternal hyperglycemia causes fetal hyperglycemia, which stimulates fetal pancreatic beta-cell hyperplasia and hyperinsulinemia. After delivery, when the maternal glucose supply is cut off, the persistent fetal hyperinsulinemia causes neonatal hypoglycemia. Distractor A is wrong because the risk is hypoglycemia, not hyperglycemia. Distractor B describes a complication of placental insufficiency and growth restriction, not macrosomia. Distractor D is not specifically linked to gestational diabetes macrosomia.

Reference: Williams Obstetrics, 26th ed.

High-yield for: NEET PGINI-CETNExTFMGEUSMLEPLABMRCP

Written and medically reviewed by the StethoPrep medical team.