title: Racial and ethnic differences in the risk of postpartum venous thromboembolism: a population-based, case-control study.
abstract: BACKGROUND
  Venous thromboembolism (VTE) is a major contributor of maternal morbidity and mortality. Whether maternal race/ethnicity is associated with the risk of postpartum VTE remains unclear.
  
  
  RESULTS
  We conducted a population-based, case-control study in Washington State, from 1987 through 2011. Cases comprised all women with selected International Classification of Diseases, Ninth Edition, Clinical Modification codes for hospitalized VTE within 3 months post-delivery. Controls were randomly selected postpartum women who did not experience a VTE. Characteristics of women and their deliveries were abstracted from birth certificates. Using logistic regression models, we compared the risk of postpartum VTE in black, Asian, and Hispanic women with that in non-Hispanic white women, after adjustment for maternal characteristics (age, body mass index, parity, education), pregnancy complications, and delivery methods.
  
  
  RESULTS
  Our study comprised 688 cases and 10 246 controls. Among controls, the mean age and body mass index were 27.5 years and 26.3 kg m(-2) , respectively. Compared with white women, black and Asian women had a greater and lower risk of postpartum VTE (adjusted odds ratio [OR] 1.50, 95% confidence interval [CI] 1.10-2.04 and OR 0.67, 95%CI 0.48-0.94, respectively). A lower risk was present in Hispanic women (adjusted OR 0.80, 95% CI 0.61-1.06) but was not statistically significant. In subgroup analyses, we observed an increased risk for black compared with white women among women who delivered via cesarean section (OR 2.03, 95% CI 1.34-3.07) but not among vaginal deliveries (OR 1.03, 95% CI 0.61-1.74).
  
  
  CONCLUSIONS
  Maternal race/ethnicity is associated with the risk of postpartum VTE, independently of other risk factors, and should be considered when assessing the use of thromboprophylaxis after delivery.
authors.affiliation: Division of Angiology and Haemostasis, Geneva University Hospitals and Faculty of Medicine, Geneva, Switzerland; Department of Epidemiology, University of Washington, Seattle, WA, USA.
authors.forename: M
authors.initials: M
authors.lastname: Blondon
authors.forename: L B
authors.initials: LB
authors.lastname: Harrington
authors.forename: M
authors.initials: M
authors.lastname: Righini
authors.forename: F
authors.initials: F
authors.lastname: Boehlen
authors.forename: H
authors.initials: H
authors.lastname: Bounameaux
authors.forename: N L
authors.initials: NL
authors.lastname: Smith
mesh_terms: D000328:Adult; D044383:Black People; D015992:Body Mass Index; D016022:Case-Control Studies; D036861:Delivery, Obstetric; D005006:Ethnicity; D005260:Female; D006630:Hispanic or Latino; D006801:Humans; D016017:Odds Ratio; D049590:Postpartum Period; D011247:Pregnancy; D011249:Pregnancy Complications, Cardiovascular; D012044:Regression Analysis; D012189:Retrospective Studies; D012307:Risk Factors; D054556:Venous Thromboembolism / Q000175:diagnosis* / Q000208:ethnology* / Q000517:prevention & control; D014861:Washington; D044465:White People; D055815:Young Adult; D001741:Black or African American
keywords: Continental Population Groups; epidemiology; ethnic groups; postpartum period; pregnancy; venous thromboembolism