title: Epidemiological investigation of a temporal increase in atonic postpartum haemorrhage: a population-based retrospective cohort study.
abstract: OBJECTIVE
  Increases in atonic postpartum haemorrhage (PPH) have been reported from several countries in recent years. We attempted to determine the potential cause of the increase in atonic and severe atonic PPH.
  
  
  METHODS
  Population-based retrospective cohort study.
  
  
  METHODS
  British Columbia, Canada, 2001-2009.
  
  
  METHODS
  All women with live births or stillbirths.
  
  
  METHODS
  Detailed clinical information was obtained for 371 193 women from the British Columbia Perinatal Data Registry. Outcomes of interest were atonic PPH and severe atonic PPH (atonic PPH with blood transfusion ≥1 unit; atonic PPH with blood transfusion ≥3 units or procedures to control bleeding), whereas determinants studied included maternal characteristics (e.g. age, parity, and body mass index) and obstetrics practice factors (e.g. labour induction, augmentation, and caesarean delivery). Year-specific unadjusted and adjusted odds ratios for the outcomes were compared using logistic regression.
  
  
  METHODS
  Atonic PPH and severe atonic PPH.
  
  
  RESULTS
  Atonic PPH increased from 4.8% in 2001 to 6.3% in 2009, atonic PPH with blood transfusion ≥1 unit increased from 16.6 in 2001 to 25.5 per 10 000 deliveries in 2009, and atonic PPH with blood transfusion ≥3 units or procedures to control bleeding increased from 11.9 to 17.6 per 10 000 deliveries. The crude 34% (95% CI 26-42%) increase in atonic PPH between 2001 and 2009 remained unchanged (42% increase, 95% CI 34-51%) after adjustment for determinants of PPH. Similarly, adjustment did not explain the increase in severe atonic PPH.
  
  
  CONCLUSIONS
  Changes in maternal characteristics and obstetric practice do not explain the recent increase in atonic and severe atonic PPH.
authors: Department of Obstetrics and Gynaecology, University of British Columbia and the Children's and Women's Health Centre of British Columbia, Vancouver, BC, Canada. azar@interchange.ubc.ca
authors: A
authors: A
authors: Mehrabadi
authors: J A
authors: JA
authors: Hutcheon
authors: L
authors: L
authors: Lee
authors: M S
authors: MS
authors: Kramer
authors: R M
authors: RM
authors: Liston
authors: K S
authors: KS
authors: Joseph
mesh_terms: D000328:Adult; D001803:Blood Transfusion / Q000706:statistics & numerical data; D001955:British Columbia / Q000453:epidemiology; D015331:Cohort Studies; D036861:Delivery, Obstetric / Q000379:methods / Q000706:statistics & numerical data; D005260:Female; D006801:Humans; D016015:Logistic Models; D016017:Odds Ratio; D006473:Postpartum Hemorrhage / Q000453:epidemiology* / Q000209:etiology / Q000628:therapy; D011247:Pregnancy; D012042:Registries; D012189:Retrospective Studies; D012307:Risk Factors; D012720:Severity of Illness Index