This 1.78-kg boy was delivered via cesarean section because of maternal preeclampsia. Prenatal sonograms obtained at 19 and 34 weeks' gestation were normal. Apgar scores were 9 and 9 at 1 and 5 minutes, respectively, and the infant's maturation was appropriate for his gestational age of 34 weeks. Results of the initial examination of the umbilical cord and placenta were normal. Some mild respiratory distress cleared within hours of birth. At age 4 days, the newborn's umbilical cord stump was noted to occasionally increase by 0.25 cm in diameter, and the cord was noted to intermittently drain clear fluid. Results of physical examination, abdominal roentgenography, and ultrasonography of the cord stump and abdomen were normal. Urine collection bags were placed on the umbilicus and penis. Within 24 hours, 10 mL of clear fluid drained from the umbilicus, and a small mucosa-lined defect was identified at the base of the cord.