Outcome of pregnancy after prenatal diagnosis of umbilical vein varix.

Previous studies of umbilical vein varix diagnosed prenatally have been small, and the results have been contradictory. We wanted to determine whether prenatally diagnosed umbilical vein varix is associated with an increased risk of fetal anomalies or poor perinatal outcomes. We identified all cases of fetal intra-abdominal umbilical vein varix diagnosed on the basis of prenatal ultrasonography at Brigham and Women's Hospital between 1988 and 1998. Cases were reviewed to determine the presence of other sonographic findings as well as pregnancy and neonatal outcomes. We identified 25 cases and included those 23 for which follow-up was available. In 11 cases (48%), pregnancies and neonatal outcomes were normal, with full-term delivery, appropriate birth weight, and no evidence of anomalies. Three cases (13%) had preterm deliveries, and 1 had Kell isoimmunization requiring postnatal transfusion. In the remaining 8 cases (35%), structural anomalies were present. One fetus had a chromosomal abnormality (69,XXX). Prenatal diagnosis of fetal umbilical vein varix appears to be associated with a high rate of fetal anomalies. Detection of an umbilical vein varix should prompt a thorough examination of the fetus, including a fetal survey and echocardiogram. Isoimmunization should be ruled out, and consideration of karyotyping should be discussed if other anomalies are present.