Isolated single umbilical artery is an independent risk factor for perinatal mortality and adverse outcomes in term neonates

Objective: To determine whether an isolated single umbilical artery (iSUA) is an independent risk factor for perinatal mortality in term neonates with normal estimated fetal weight (EFW) prior to delivery. Method: A population-based study was conducted, including all deliveries occurring between 1993 and 2013, in a tertiary medical center. Pregnancies with and without iSUA were compared. Multiple gestations, chromosomal, and structural abnormalities were excluded from the cohort. Only pregnancies delivered at term with normal EFW evaluated prior to delivery were included. Stratified analysis was performed using multiple logistic regression models to evaluate the risk of adverse outcomes and perinatal mortality for iSUA fetuses. Results: During the study period, 233,123 deliveries occurred at “Soroka” University Medical Center, out of which 786 (0.3 %) were diagnosed with iSUA. Different pregnancy complications were more common with iSUA fetuses including: placental abruption (OR = 3.4), true knot of cord (OR = 3.5) and cord prolapse (OR = 2.8). Induction of labor and cesarean delivery were also more common in these pregnancies (OR = 1.5 and OR = 1.9, respectively). iSUA neonates had lower Apgar scores at 1 and 5 min (OR = 1.8, OR = 1.9, respectively) compared to the control group and perinatal mortality rates were higher both antenatally (IUFD, OR = 8.1) and postnatally (PPD, OR = 6.1). Conclusion: iSUA appears to be an independent predictor of adverse perinatal outcomes in term neonates.