title: Hospital volume, provider volume, and complications after childbirth in U.S. hospitals.
abstract: OBJECTIVE
  To examine the relationship between both hospital and provider case volume and obstetric complication rates in U.S. hospitals.
  
  
  METHODS
  This was a nationwide retrospective cohort study of women admitted to acute care U.S. hospitals for childbirth in 2007. We examined four categories of maternal complications (lacerations, hemorrhage, infections, and thromboses) and created a composite measure. We examined the relationship of hospital volume, provider volume, and odds of complications.
  
  
  RESULTS
  We found no consistent relationship between hospital volume and rates of maternal complications. In contrast, we found that women cared for by providers in the lowest quartile of provider volume (fewer than seven deliveries per year) had a 50% higher odds of complications compared with women cared for by obstetricians in the highest quartile (odds ratio 1.5, 95% confidence interval, 1.3-1.7, P<.001). Each of the individual complications occurred more frequently among the lowest-volume providers compared with others. Models that adjusted for hospital characteristics and cesarean delivery rate had only modest effects.
  
  
  CONCLUSIONS
  Individual providers with a low volume of deliveries have greater maternal complication rates than providers with a high volume. If volume is causally related to lower complication rates, strategies for improving care for women during childbirth may include selective referral to higher-volume providers or additional training for low-volume providers to ensure better outcomes.
  
  
  METHODS
  III.
authors.affiliation: From the Department of Obstetrics and Gynecology, Massachusetts General Hospital; the Department of Health Policy and Management, Harvard School of Public Health; the Department of Medicine, Brigham and Women's Hospital; and VA Boston Healthcare System, Boston, Massachusetts.
authors.forename: Vanitha
authors.initials: V
authors.lastname: Janakiraman
authors.forename: Jane
authors.initials: J
authors.lastname: Lazar
authors.forename: Karen E
authors.initials: KE
authors.lastname: Joynt
authors.forename: Ashish K
authors.initials: AK
authors.lastname: Jha
mesh_terms: D000328:Adult; D002585:Cesarean Section / Q000706:statistics & numerical data; D002983:Clinical Competence; D005260:Female; D006761:Hospitals / Q000706:statistics & numerical data*; D006801:Humans; D016015:Logistic Models; D007744:Obstetric Labor Complications / Q000453:epidemiology*; D009774:Obstetrics / Q000706:statistics & numerical data*; D016017:Odds Ratio; D006473:Postpartum Hemorrhage; D011247:Pregnancy; D011256:Pregnancy Outcome / Q000453:epidemiology*; D011644:Puerperal Disorders / Q000453:epidemiology*; D011645:Puerperal Infection / Q000453:epidemiology*; D012189:Retrospective Studies; D012307:Risk Factors; D014481:United States / Q000453:epidemiology