Aim: To identify whether an isolated single umbilical artery (ISUA) impacts pregnancy outcome and delivery mode in single and full-term births.
Methods: A retrospective study was carried out on 93,592 pregnant women (singleton pregnancy; full-term birth; no known fetal chromosomal and structural anomalies) who gave birth between January 2011 and January 2012 in 39 hospitals within China. Pregnancy outcomes and modes of delivery were compared between research (313 cases with ISUAs) and comparison groups (1,252 cases with three-vessel cords in a 1:4 ratio randomly matched by parity).
Results: The birth weights (3264.71 ± 469.95 g vs 3340.76 ± 434.25 g, P = 0.001), birth lengths (48.51 ± 2.84 cm vs 49.99 ± 1.65 cm, P = 0.000), placental weights (511.31 ± 76.43 g vs 545.31 ± 85.06 g, P = 0.002), umbilical cord lengths (52.64 ± 8.82 cm vs 54.08 ± 7.81 cm, P = 0.002) and Apgar scores within one min of birth (8.83 ± 0.96 vs 9.57 ± 0.75, P = 0.000) of newborn infants were significantly lower in the research than the comparison group; the incidence of small for gestational age (10.94% vs 5.39%, P = 0.000) and low birth weight infants (6.69% vs 1.98%, P = 0.000) were significantly higher in the research group. There was no significant difference in fetal/placental weight, incidence of velamentous cord insertions, 1 min Apgar score < 7, 5 min Apgar score < 7 or vaginal or emergency cesarean delivery rates as a result of fetal factors between the two groups.
Conclusion: An ISUA is associated with an adverse pregnancy outcome; however does not decrease the rate of vaginal delivery in full-term births.
Keywords: delivery mode; full-term birth; isolated single umbilical artery; perinatal outcome; pregnancy.
© 2016 Japan Society of Obstetrics and Gynecology.