title: Risk for postpartum hemorrhage, transfusion, and hemorrhage-related morbidity at low, moderate, and high volume hospitals.
abstract: OBJECTIVE
  The objective of this study was to characterize risk for and temporal trends in postpartum hemorrhage across hospitals with different delivery volumes.
  
  
  METHODS
  This study used the Nationwide Inpatient Sample (NIS) to characterize risk for postpartum hemorrhage from 1998 to 2011. Hospitals were classified as having either low, moderate or high delivery volume (≤1000, 1001 to 2000, >2000 deliveries per year, respectively). The primary outcomes included postpartum hemorrhage, transfusion, and related severe maternal morbidity. Adjusted models were created to assess factors associated with hemorrhage and transfusion.
  
  
  RESULTS
  Of 55,140,088 deliveries included for analysis 1,512,212 (2.7%) had a diagnosis of postpartum hemorrhage and 361,081 (0.7%) received transfusion. Risk for morbidity and transfusion increased over the study period, while the rate of hemorrhage was stable ranging from 2.5 to 2.9%. After adjustment, hospital volume was not a major risk factor for transfusion or hemorrhage.
  
  
  CONCLUSIONS
  While obstetric volume does not appear to be a major risk factor for either transfusion or hemorrhage, given that transfusion and hemorrhage-related maternal morbidity are increasing across hospital volume categories, there is an urgent need to improve obstetrical care for postpartum hemorrhage. Those risk factors are able to discriminate women at increased risk supports routine use of hemorrhage risk assessment.
authors.affiliation: a Department of Obstetrics and Gynecology , College of Physicians and Surgeons, Columbia University , New York , NY , USA.
authors.forename: Audrey A
authors.initials: AA
authors.lastname: Merriam
authors.affiliation: a Department of Obstetrics and Gynecology , College of Physicians and Surgeons, Columbia University , New York , NY , USA.
authors.forename: Jason D
authors.initials: JD
authors.lastname: Wright
authors.affiliation: a Department of Obstetrics and Gynecology , College of Physicians and Surgeons, Columbia University , New York , NY , USA.
authors.forename: Zainab
authors.initials: Z
authors.lastname: Siddiq
authors.affiliation: a Department of Obstetrics and Gynecology , College of Physicians and Surgeons, Columbia University , New York , NY , USA.
authors.forename: Mary E
authors.initials: ME
authors.lastname: D'Alton
authors.affiliation: a Department of Obstetrics and Gynecology , College of Physicians and Surgeons, Columbia University , New York , NY , USA.
authors.forename: Alexander M
authors.initials: AM
authors.lastname: Friedman
authors.affiliation: a Department of Obstetrics and Gynecology , College of Physicians and Surgeons, Columbia University , New York , NY , USA.|b Department of Epidemiology , Joseph L. Mailman School of Public Health, Columbia University , New York , NY , USA.
authors.forename: Cande V
authors.initials: CV
authors.lastname: Ananth
authors.affiliation: c Division of Pharmacoepidemiology and Pharmacoeconomics, Department of Medicine, Brigham and Women's Hospital; the Department of Anesthesiology, Critical Care, and Pain Medicine , Harvard Medical School , Boston , MA , USA.
authors.forename: Brian T
authors.initials: BT
authors.lastname: Bateman
mesh_terms: D000293:Adolescent; D000328:Adult; D001803:Blood Transfusion / Q000706:statistics & numerical data; D005260:Female; D061847:Hospitals, High-Volume / Q000706:statistics & numerical data*; D061846:Hospitals, Low-Volume / Q000706:statistics & numerical data*; D006801:Humans; D008875:Middle Aged; D006473:Postpartum Hemorrhage / Q000453:epidemiology* / Q000628:therapy; D011247:Pregnancy; D014481:United States / Q000453:epidemiology; D055815:Young Adult
keywords: Obstetric hemorrhage; maternal morbidity; maternal safety