Which is a risk factor for renal venous thrombosis in neonates?

• A. Maternal anemia
• B. Maternal diabetes mellitus
• C. Polyhydramnios
• D. Maternal hypertension

Answer: (B)

Renal venous thrombosis in newborns develops in a prothrombotic, hyperviscous state of the neonate. Infants of mothers with diabetes mellitus are at higher risk because maternal diabetes often causes fetal hypoxia and polycythemia, which raise the hematocrit and blood viscosity. This hyperviscosity promotes clot formation in small vessels, including the renal vein. Dehydration after birth and potential perinatal stress in infants of diabetic mothers further contribute to a tendency to thrombose. Polyhydramnios commonly seen in diabetic pregnancies reflects fetal polyuria from hyperglycemia but is not itself a direct cause of neonatal RVT. Hence maternal diabetes mellitus is the most plausible risk factor among the options.