title: Identifying women most likely to benefit from prevention strategies for postpartum hemorrhage.
abstract: OBJECTIVE
  To identify women who are most likely to benefit from primary prevention strategies for postpartum hemorrhage (PPH).
  
  
  METHODS
  In a retrospective patient cohort, we applied recursive partitioning algorithms to identify the most discriminant risk factors and their interactions, and calculated the 'number needed to treat' to prevent a single case of PPH (estimated blood loss >1000 ml).
  
  
  RESULTS
  By delivery category, the highest risk groups with 'number needed to treat' ranging from 4 to 7 were: (1) vaginal delivery (PPH=0.7% of 16 218)-macrosomia with gestational diabetes and manual removal of the placenta; (2) primary cesarean (PPH=18.7% of 2696)-macrosomia and multiparity; and (3) repeat cesarean (PPH=16.0% of 1832)-uterine incision other than low transverse and failed vaginal birth after cesarean.
  
  
  CONCLUSIONS
  Clinical profiles that identify women at risk for PPH can provide a foundation for the development of primary prevention strategies.
authors.affiliation: Department of Obstetrics and Gynecology, David Geffen School of Medicine at UCLA, Los Angeles, CA 90033, USA.
authors.forename: M C
authors.initials: MC
authors.lastname: Lu
authors.forename: L M
authors.initials: LM
authors.lastname: Korst
authors.forename: M
authors.initials: M
authors.lastname: Fridman
authors.forename: E
authors.initials: E
authors.lastname: Muthengi
authors.forename: K D
authors.initials: KD
authors.lastname: Gregory
mesh_terms: D000465:Algorithms; D017604:Cesarean Section, Repeat / Q000009:adverse effects*; D005260:Female; D005320:Fetal Macrosomia; D006801:Humans; D008485:Medical Audit; D016017:Odds Ratio; D006473:Postpartum Hemorrhage / Q000209:etiology* / Q000517:prevention & control*; D011247:Pregnancy; D012189:Retrospective Studies; D012307:Risk Factors