title: Single umbilical artery and its associated findings.
abstract: OBJECTIVE
  To estimate whether the presence of a single umbilical artery is associated with intrauterine growth restriction (IUGR), fetal demise, or major congenital anomalies.
  
  
  METHODS
  We performed a retrospective cohort study of all consecutive singleton pregnancies undergoing routine anatomic survey between 1990 and 2007 at a major tertiary medical center. Two dedicated research nurses obtained complete pregnancy outcome data in an ongoing manner. Pregnancies with a diagnosis of single umbilical artery were compared with those with two umbilical arteries. The primary outcomes were IUGR (less than 10th percentile), renal, and cardiac anomalies. Multivariable logistic regression was used to refine the risk association between single umbilical artery and adverse pregnancy outcomes while adjusting for confounding effects.
  
  
  RESULTS
  Of 72,373 pregnancies, 64,047 (88.5%) had pregnancy follow-up information and were available for this analysis. There were 392 cases of single umbilical artery (0.61%) diagnosed at anatomic survey; slightly lower than previously reported. Single umbilical artery as compared with double umbilical artery was associated with increased risk of renal anomalies (adjusted odds ratio [OR] 3.0, 95% confidence interval [CI] 1.9-4.9, P<.01) and cardiac anomalies (adjusted OR 20.3, 95% CI 13.5-30.4, P<.01). Single umbilical artery was also associated with an increased risk of IUGR (adjusted OR 2.1, 95% CI 1.6-2.7, P<.01), even after excluding all fetuses with known anomalies.
  
  
  CONCLUSIONS
  Our data suggest an increased risk of IUGR when the diagnosis of single umbilical artery is made, making a clinical recommendation for serial growth assessments in the setting of single umbilical artery reasonable.
authors.affiliation: From the Department of Obstetrics and Gynecology, Washington University in St. Louis, St. Louis, Missouri.
authors.forename: Meiling
authors.initials: M
authors.lastname: Hua
authors.forename: Anthony O
authors.initials: AO
authors.lastname: Odibo
authors.forename: George A
authors.initials: GA
authors.lastname: Macones
authors.forename: Kimberly A
authors.initials: KA
authors.lastname: Roehl
authors.forename: James P
authors.initials: JP
authors.lastname: Crane
authors.forename: Alison G
authors.initials: AG
authors.lastname: Cahill
mesh_terms: D000328:Adult; D015986:Confounding Factors, Epidemiologic; D016640:Diabetes, Gestational / Q000453:epidemiology; D005260:Female; D005313:Fetal Death / Q000453:epidemiology; D005317:Fetal Growth Retardation / Q000453:epidemiology* / Q000473:pathology; D006801:Humans; D016015:Logistic Models; D011225:Pre-Eclampsia / Q000453:epidemiology; D011247:Pregnancy; D011256:Pregnancy Outcome; D012189:Retrospective Studies; D016216:Ultrasonography, Prenatal; D014469:Umbilical Arteries / Q000002:abnormalities* / Q000000981:diagnostic imaging; D055815:Young Adult
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