Perinatal outcome following fetal single umbilical artery diagnosis

Objective: We report the frequency of associated congenital abnormalities in fetuses with a single umbilical artery as well as the sensitivity, specificity, positive predictive value and negative predictive value of ultrasound for detecting these abnormalities. We also report the pregnancy outcome of fetuses complicated by single umbilical artery, both isolated and with other congenital anomalies. Methods: All pregnancies complicated by fetal single umbilical artery from 1995 to 1999 were identified. A retrospective chart review was performed on both the prenatal records and the ultrasound records of these pregnancies, determining the nature and incidence of other congenital abnormalities. Delivery data were collected to include gestational age at delivery, Apgar score, birth weight, mode of delivery, fetal gender and any complications. Results: Ninety-two pregnancies were identified with a fetal single umbilical artery, of which outcome data were available for 65. Forty-eight (74%) cases were identified as isolated single umbilical artery. Seventeen (26%) cases had other congenital abnormalities. High-resolution ultrasound had 100% sensitivity and specificity for identifying single umbilical artery and an 85% sensitivity and 98% specificity for detecting other congenital abnormalities. Compared to isolated single umbilical artery, pregnancies complicated by single umbilical artery with other abnormalities had a statistically significantly increased rate of fetal aneuploidy, lower birth weight, preterm delivery and Cesarean delivery. Conclusion: Pregnancies complicated by fetal single umbilical artery, especially when associated with other congenital abnormalities, are at increased risk for adverse pregnancy outcome.