Prenatal diagnosis of abnormal persistence of the right or left umbilical vein: report of 4 cases and literature review.

Four cases of prenatally diagnosed abnormal persistence of an umbilical vein are presented. Of the 4 cases, 2 are in association with congenital heart disease, 2 are in the setting of abdominal visceral situs inversus, and 1 is with extrahepatic persistence of an umbilical vein. Whereas persistent right umbilical vein may occur in 0.2% to 0.4% of fetuses undergoing screening prenatal ultrasonography, reports of an extrahepatic course are rare. A review of the 62 reported cases of prenatally diagnosed abnormally persistent umbilical vein revealed 9 fetuses (15%) with a congenital cardiovascular malformation, of which 6 were significant enough to likely require surgery. Other organ system malformations were present in 9 patients (15%). The prevalence of congenital cardiovascular malformations was 3 (7%) of 42 when combining 2 large series that were relatively unbiased for referrals for possible heart disease. Detailed evaluation by ultrasonography and fetal echocardiography should be used for prenatally diagnosed cases of abnormal persistence of an umbilical vein.