title: The risk of fetal death in nonanomalous pregnancies affected by polyhydramnios.
abstract: OBJECTIVE
  The objective of the study was to evaluate the ongoing risk of intrauterine fetal demise (IUFD) in nonanomalous pregnancies affected by polyhydramnios.
  
  
  METHODS
  We analyzed a retrospective cohort of all singleton, nonanomalous births in California between 2005 and 2008 as recorded in a statewide birth certificate registry. We included all births between 24+0 and 41+6 weeks' gestational age, excluding multiple gestations, major congenital anomalies, and pregnancies affected by oligohydramnios. Polyhydramnios was identified by International Classification of Diseases, ninth revision, codes. χ(2) tests were used to compare the dichotomous outcomes, and multivariable logistic regression analyses were then performed to control for potential confounders. We analyzed the data for pregnancies affected and unaffected by polyhydramnios. The IUFD risk was expressed as a rate per 10,000.
  
  
  RESULTS
  The risk of IUFD in pregnancies affected by polyhydramnios was greater at every gestational age compared with unaffected pregnancies. The IUFD risk in pregnancies affected by polyhydramnios was more than 7 times higher than unaffected pregnancies at 37 weeks at a rate of 18.0 (95% confidence interval [CI], 9.0-32.6) vs 2.4 (95% CI, 2.0-2.5) and was 11-fold higher by 40 weeks' gestational age at a rate of 66.3 (95% CI, 10.8-68.6) vs 6.0 (95% CI, 5.1-6.3) in unaffected pregnancies. When adjusted for multiple confounding variables, the presence of polyhydramnios remained associated with an increased odds of IUFD in nonanomalous singleton pregnancies, with an adjusted odds ratio of 5.5 (95% CI, 4.1-7.6).
  
  
  CONCLUSIONS
  Ongoing risk of IUFD is greater in low-risk pregnancies affected by polyhydramnios at all gestational ages compared with unaffected pregnancies with the greatest increase in risk at term. Although further study is needed to explore the underlying etiology of polyhydramnios in these cases, the identification of polyhydramnios alone may warrant increased antenatal surveillance.
authors.affiliation: Department of Obstetrics and Gynecology, Brigham and Women's Hospital, Massachusetts General Hospital, Boston, MA. Electronic address: rpilliod@partners.org.
authors.forename: Rachel A
authors.initials: RA
authors.lastname: Pilliod
authors.affiliation: Department of Obstetrics and Gynecology, University of Utah School of Medicine, Salt Lake City, UT.
authors.forename: Jessica M
authors.initials: JM
authors.lastname: Page
authors.affiliation: Division of Maternal-Fetal Medicine, Department of Obstetrics and Gynecology, Oregon Health and Science University, Portland, OR.
authors.forename: Richard M
authors.initials: RM
authors.lastname: Burwick
authors.affiliation: Division of Maternal-Fetal Medicine, Department of Obstetrics and Gynecology, Massachusetts General Hospital, Boston, MA.
authors.forename: Anjali J
authors.initials: AJ
authors.lastname: Kaimal
authors.affiliation: Division of Maternal-Fetal Medicine, Department of Obstetrics and Gynecology, University of California, Davis, School of Medicine, Sacramento, CA.
authors.forename: Yvonne W
authors.initials: YW
authors.lastname: Cheng
authors.affiliation: Division of Maternal-Fetal Medicine, Department of Obstetrics and Gynecology, Oregon Health and Science University, Portland, OR.
authors.forename: Aaron B
authors.initials: AB
authors.lastname: Caughey
mesh_terms: D000328:Adult; D002140:California; D015331:Cohort Studies; D005260:Female; D005313:Fetal Death / Q000209:etiology*; D006801:Humans; D016015:Logistic Models; D008297:Male; D006831:Polyhydramnios / Q000401:mortality*; D011247:Pregnancy; D012042:Registries; D012189:Retrospective Studies; D012307:Risk Factors
keywords: antenatal testing; intrauterine fetal demise; polyhydramnios; stillbirth