Perinatal outcomes in singleton pregnancies with a single umbilical artery

OBJECTIVE: To analyze perinatal outcomes in singleton pregnancies with a single umbilical artery (SUA) as an isolated finding with no other underlying disorders. METHODS: This retrospective observational study compared a group of pregnancies with SUA (n = 127) and a group with a normal 3-vessel umbilical cord (n = 27 752). The study variables comprised maternal and obstetric characteristics and perinatal outcomes. RESULTS: The frequency of SUA was 0.45%. Pregnancies with SUA ended more frequently with cesarean delivery, and had a higher risk that the indication for cesarean delivery was non-reassuring fetal heart rate (NRFHR). Neonates in the SUA group had a lower weight for gestational age, and a higher risk of low umbilical cord blood pH. CONCLUSION: Obstetricians should monitor fetal growth closely in pregnancies with SUA, and be alert to NRFHR during labor and delivery.