The clinical significance of a single umbilical artery as an isolated finding on prenatal ultrasound.

Objective: To evaluate the perinatal outcome in fetuses with single umbilical artery detected on targeted prenatal ultrasound without other anomalies.

Methods: During a 3.5-year period, an isolated single umbilical artery was suspected on prenatal ultrasound examination in 57 fetuses evaluated at two referral centers. Targeted imaging to rule out concurrent fetal anomalies was normal in all cases. Pregnancy and perinatal outcome data were retrieved by review of the medical records or from conversations with referring physicians. Complete follow-up was available in 50 cases.

Results: A two-vessel umbilical cord was confirmed at birth in 50 neonates. The mean gestational age at delivery was 38.6 +/- 2.8 weeks; the mean birth weight was 3202.8 +/- 835.8 g. Seventeen patients (34%) underwent genetic amniocentesis, and all fetuses had a normal karyotype. The only neonate ascertained to have a congenital anomaly after birth was diagnosed with total anomalous pulmonary venous return. This neonate underwent a corrective surgical procedure and is thriving with no apparent problems at 3.5 years of age. There were no perinatal deaths.

Conclusion: In the absence of additional sonographically detectable anomalies, an isolated single umbilical artery does not seem to affect clinical outcome and therefore should not alter routine obstetric management.