title: Preterm premature rupture of membranes, intrauterine infection, and oligohydramnios: risk factors for placental abruption.
abstract: OBJECTIVE
  To examine whether preterm premature rupture of membranes (PROM), intrauterine infection, and oligohydramnios are risk factors for placental abruption.
  
  
  METHODS
  Data for this retrospective cohort study were derived from the 1988 National Maternal and Infant Health Survey (N = 11,777). Association between abruption and these clinical risk factors was expressed as relative risk (RR) and 95% confidence interval (CI), with multivariate adjustment for potential confounders.
  
  
  RESULTS
  The overall incidence of abruption was 0.87%. The risk of abruption was 3.58-fold higher (95% CI 1.74-7.39) among women with preterm PROM (2.29%) compared with women with intact membranes (0.86%). The rates of abruption among women with and without intrauterine infection were 4.81% and 0.83%, respectively (RR 9.71, 95% CI 3.23-29.17). However, oligohydramnios was not associated with abruption (1.46% compared with 0.87%; RR 2.09, 95% CI 0.92-5.31). Compared with women with intact membranes, the RR for abruption among preterm PROM and whose membranes were ruptured for 24-47 hours and 48 hours or more before delivery, respectively, were 2.37 (95% CI 0.99-9.09), and 9.87 (95% CI 3.57-27.82). When preterm PROM was accompanied by intrauterine infections, the RR for abruption was 9.03 (95% CI 2.80-29.15) compared with women with intact membranes and no infections. Similarly, preterm PROM accompanied by oligohydramnios conferred over a 7.17-fold risk (95% CI 1.35-38.10) for abruption compared with women with neither of these 2 conditions.
  
  
  CONCLUSIONS
  Women presenting with preterm PROM are at increased risk of developing abruption, with the risk being higher either in the presence of intrauterine infections or oligohydramnios. Physicians managing patients with preterm PROM should be aware that these patients are at increased risk of developing abruption after 24 hours following preterm PROM.
authors.affiliation: Department of Obstetrics, Gynecology, and Reproductive Sciences, Robert Wood Johnson Medical School/Robert Wood Johnson University Hospital, University of Medicine and Dentistry of New Jersey, New Brunswick, New Jersey, USA. cande.ananth@umdnj.edu
authors.forename: Cande V
authors.initials: CV
authors.lastname: Ananth
authors.forename: Yinka
authors.initials: Y
authors.lastname: Oyelese
authors.forename: Neela
authors.initials: N
authors.lastname: Srinivas
authors.forename: Lami
authors.initials: L
authors.lastname: Yeo
authors.forename: Anthony M
authors.initials: AM
authors.lastname: Vintzileos
mesh_terms: D000037:Abruptio Placentae / Q000209:etiology*; D000328:Adult; D016001:Confidence Intervals; D005260:Female; D005322:Premature Rupture of Fetal Membranes / Q000150:complications*; D006801:Humans; D016104:Oligohydramnios / Q000150:complications*; D011247:Pregnancy; D011251:Pregnancy Complications, Infectious; D012307:Risk Factors