title: First-birth cesarean and placental abruption or previa at second birth(1).
abstract: OBJECTIVE
  To assess the association between first-birth cesarean delivery and second-birth placental abruption and previa.
  
  
  METHODS
  We conducted a population-based, retrospective cohort analysis using data from the Washington State Birth Events Record Database. The study cohort included all primiparas who gave birth to live singleton infants in nonfederal short-stay hospitals from January 1, 1987, through December 31, 1996, and who had second singleton births during the same period (n = 96,975). Odds ratios (ORs) and 95% confidence intervals (CIs) were calculated for placental abruption or previa at second births associated with first-birth cesareans.
  
  
  RESULTS
  Among our study cohort, abruptio placentae complicated 11.5 per 1000 and placenta previa 5.2 per 1000 singleton deliveries at second births. In logistic regression analyses adjusted for maternal age, women with first-birth cesareans had significantly increased risk of abruptio placentae (OR 1.3, 95% CI 1.1, 1.5), and placenta previa (OR 1.4, 95% CI 1.1, 1.6) at second births, compared with women with prior vaginal deliveries.
  
  
  CONCLUSIONS
  We found moderately increased risk of placental abruption and previa as a long-term effect of prior cesarean delivery on second births.
authors.affiliation: Department of Health Services, School of Public Health and Community Medicine, University of Washington, Seattle, Washington, USA. minot@u.washington.edu
authors.forename: M
authors.initials: M
authors.lastname: Lydon-Rochelle
authors.forename: V L
authors.initials: VL
authors.lastname: Holt
authors.forename: T R
authors.initials: TR
authors.lastname: Easterling
authors.forename: D P
authors.initials: DP
authors.lastname: Martin
mesh_terms: D000037:Abruptio Placentae / Q000453:epidemiology* / Q000209:etiology; D000293:Adolescent; D000328:Adult; D001722:Birth Order; D002585:Cesarean Section / Q000009:adverse effects / Q000379:methods / Q000706:statistics & numerical data*; D015331:Cohort Studies; D016001:Confidence Intervals; D005260:Female; D006801:Humans; D015994:Incidence; D016017:Odds Ratio; D010298:Parity; D010923:Placenta Previa / Q000453:epidemiology* / Q000209:etiology; D011159:Population Surveillance; D011247:Pregnancy; D011336:Probability; D012189:Retrospective Studies; D018570:Risk Assessment; D012307:Risk Factors; D014861:Washington / Q000453:epidemiology