title: Pre-eclampsia increases the risk of postpartum haemorrhage: a nationwide cohort study in the Netherlands.
abstract: BACKGROUND
  Postpartum haemorrhage is a leading cause of maternal morbidity and mortality worldwide. Identifying risk indicators for postpartum haemorrhage is crucial to predict this life threatening condition. Another major contributor to maternal morbidity and mortality is pre-eclampsia. Previous studies show conflicting results in the association between pre-eclampsia and postpartum haemorrhage. The primary objective of this study was to investigate the association between pre-eclampsia and postpartum haemorrhage. Our secondary objective was to identify other risk indicators for postpartum haemorrhage in the Netherlands.
  
  
  METHODS
  A nationwide cohort was used, containing prospectively collected data of women giving birth after 19 completed weeks of gestation from January 2000 until January 2008 (n =  1,457,576). Data were extracted from the Netherlands Perinatal Registry, covering 96% of all deliveries in the Netherlands. The main outcome measure, postpartum haemorrhage, was defined as blood loss of ≥1000 ml in the 24 hours following delivery. The association between pre-eclampsia and postpartum haemorrhage was investigated with uni- and multivariable logistic regression analyses.
  
  
  RESULTS
  Overall prevalence of postpartum haemorrhage was 4.3% and of pre-eclampsia 2.2%. From the 31 560 women with pre-eclampsia 2 347 (7.4%) developed postpartum haemorrhage, compared to 60 517 (4.2%) from the 1 426 016 women without pre-eclampsia (odds ratio 1.81; 95% CI 1.74 to 1.89). Risk of postpartum haemorrhage in women with pre-eclampsia remained increased after adjusting for confounders (adjusted odds ratio 1.53; 95% CI 1.46 to 1.60).
  
  
  CONCLUSIONS
  Women with pre-eclampsia have a 1.53 fold increased risk for postpartum haemorrhage. Clinicians should be aware of this and use this knowledge in the management of pre-eclampsia and the third stage of labour in order to reach the fifth Millenium Developmental Goal of reducing maternal mortality ratios with 75% by 2015.
authors.affiliation: Department of Obstetrics, Leiden University Medical Centre, Leiden, The Netherlands.
authors.forename: Joost F
authors.initials: JF
authors.lastname: von Schmidt auf Altenstadt
authors.affiliation: The Netherlands Perinatal Registry, Utrecht, The Netherlands.
authors.forename: Chantal W P M
authors.initials: CW
authors.lastname: Hukkelhoven
authors.affiliation: Department of Obstetrics, Leiden University Medical Centre, Leiden, The Netherlands ; Department of Medical Humanities, EMGO Institute for Health and Care Research, VU University Medical Centre, Amsterdam, The Netherlands.
authors.forename: Jos
authors.initials: J
authors.lastname: van Roosmalen
authors.affiliation: Department of Obstetrics, Leiden University Medical Centre, Leiden, The Netherlands.
authors.forename: Kitty W M
authors.initials: KW
authors.lastname: Bloemenkamp
mesh_terms: D000328:Adult; D005260:Female; D006801:Humans; D009426:Netherlands / Q000453:epidemiology; D006473:Postpartum Hemorrhage / Q000453:epidemiology / Q000209:etiology*; D011225:Pre-Eclampsia / Q000453:epidemiology; D011247:Pregnancy; D011248:Pregnancy Complications; D055815:Young Adult