title: Gestational age-specific severe maternal morbidity associated with labor induction.
abstract: OBJECTIVE
  The purpose of this study was to examine the association between labor induction and gestational age-specific severe maternal morbidity.
  
  
  METHODS
  Our study was restricted to women who delivered singletons at 37-42 weeks' gestation who had no pregnancy complications from 2003-2010 (n = 1,601,253) in Canada (excluding Quebec). Using a pregnancies-at-risk approach, the week-specific rates of specific morbidity after induction were contrasted with rates among ongoing pregnancies. Logistic regression was used to adjust for confounders.
  
  
  RESULTS
  Induction increased the rate of postpartum hemorrhage that required blood transfusion at 38 weeks' gestation (adjusted rate ratio, 1.28; 95% confidence interval, 1.11-1.49) and 39 weeks' gestation (adjusted rate ratio, 1.21; 95% confidence interval, 1.06-1.38). Induction was also associated with higher rates of pueperal sepsis at 38 and 39 weeks' gestation and venous thromboembolism at 38 weeks' gestation. The absolute increase in morbidity rates was small; the number needed to harm was large (eg, 1270 for postpartum hemorrhage with blood transfusion at 38 weeks' gestation).
  
  
  CONCLUSIONS
  Among women without pregnancy complications, induction at earlier term is associated with higher rates of specific severe maternal morbidity, although absolute risks are low.
authors.affiliation: Health Surveillance and Epidemiology Division, Center for Chronic Disease Prevention, Public Health Agency of Canada, Ottawa, Ontario, Canada. shiliang.liu@phac-aspc.gc.ca
authors.forename: Shiliang
authors.initials: S
authors.lastname: Liu
authors.forename: K S
authors.initials: KS
authors.lastname: Joseph
authors.forename: Jennifer A
authors.initials: JA
authors.lastname: Hutcheon
authors.forename: Sharon
authors.initials: S
authors.lastname: Bartholomew
authors.forename: Juan Andrés
authors.initials: JA
authors.lastname: León
authors.forename: Mark
authors.initials: M
authors.lastname: Walker
authors.forename: Michael S
authors.initials: MS
authors.lastname: Kramer
authors.forename: Robert M
authors.initials: RM
authors.lastname: Liston
mesh_terms: D000328:Adult; D005260:Female; D005865:Gestational Age; D006801:Humans; D007751:Labor, Induced / Q000009:adverse effects*; D016015:Logistic Models; D008423:Maternal Age; D009017:Morbidity; D011247:Pregnancy
keywords: labor induction; pregnancy complication; severe maternal morbidity