title: Impact of isolated single umbilical artery on pregnancy outcome and delivery in full-term births.
abstract: OBJECTIVE
  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.
  
  
  CONCLUSIONS
  An ISUA is associated with an adverse pregnancy outcome; however does not decrease the rate of vaginal delivery in full-term births.
authors.affiliation: Perinatal medicine department, Beijing Obstetrics and Gynecology Hospital, Capital Medical University, Beijing, China.
authors.forename: Nan
authors.initials: N
authors.lastname: Shen
authors.affiliation: Perinatal medicine department, Beijing Obstetrics and Gynecology Hospital, Capital Medical University, Beijing, China.
authors.forename: Weiyuan
authors.initials: W
authors.lastname: Zhang
authors.affiliation: Perinatal medicine department, Beijing Obstetrics and Gynecology Hospital, Capital Medical University, Beijing, China.
authors.forename: Guanghui
authors.initials: G
authors.lastname: Li
mesh_terms: D000328:Adult; D001034:Apgar Score; D001724:Birth Weight; D002585:Cesarean Section; D002681:China; D036861:Delivery, Obstetric / Q000379:methods*; D005260:Female; D005865:Gestational Age; D006801:Humans; D007231:Infant, Newborn; D009929:Organ Size; D010920:Placenta / Q000473:pathology; D011247:Pregnancy; D011256:Pregnancy Outcome; D012189:Retrospective Studies; D058529:Single Umbilical Artery / Q000473:pathology / Q000503:physiopathology*; D047929:Term Birth; D014470:Umbilical Cord / Q000473:pathology
keywords: delivery mode; full-term birth; isolated single umbilical artery; perinatal outcome; pregnancy