title: Clinical validation of risk stratification criteria for peripartum hemorrhage.
abstract: OBJECTIVE
  To determine whether the California Maternal Quality Care Collaborative risk groups predicted the risk of peripartum hemorrhage and to determine which women should have peripartum pretransfusion testing performed.
  
  
  METHODS
  Over a 1-year period, 10,134 women who delivered at a single hospital were included in this retrospective cohort study. The majority of the California Maternal Quality Care Collaborative risk factors were assessed retrospectively. Each mother was assigned to one of the three peripartum hemorrhage risk groups according to the guidelines. The individual peripartum hemorrhage risk factors and the three risk groups correlated with the occurrence of a significant peripartum hemorrhage (a hemorrhage requiring transfusion of 1 unit or more of red blood cells). Other risk factors for peripartum hemorrhage were assessed and a modified high-risk category was created.
  
  
  RESULTS
  The incidence of a significant peripartum hemorrhage within each group was as follows: low (0.8%); medium (2.0%); and high (7.3%). High included an increase that was statistically significant (P<.001). All of the assessed California Maternal Quality Care Collaborative risk criteria were significantly associated with an increased peripartum hemorrhage rate (P≤.02) except macrosomnia and morbid obesity. Other risk factors not included in the California Maternal Quality Care Collaborative criteria (preterm delivery, uterine rupture, hypertension, previous cesarean delivery, and a model of accreta or percreta) also correlated with peripartum hemorrhage. This modified risk group included 85% of those women with significant hemorrhage; however, 45% of women were included and only 2.6% of this modified group hemorrhaged.
  
  
  CONCLUSIONS
  The California Maternal Quality Care Collaborative risk stratification showed an increasing risk for transfusion as the risk grade increased. Women in the California Maternal Quality Care Collaborative high-risk group (or as determined by their providers) should have pretransfusion testing performed.
  
  
  METHODS
  II.
authors.affiliation: University of Pittsburgh School of Medicine, the Departments of Anesthesiology and Pathology, University of Pittsburgh, and the Institute for Transfusion Medicine, Pittsburgh, Pennsylvania.
authors.forename: Andrew J
authors.initials: AJ
authors.lastname: Dilla
authors.forename: Jonathan H
authors.initials: JH
authors.lastname: Waters
authors.forename: Mark H
authors.initials: MH
authors.lastname: Yazer
mesh_terms: D000328:Adult; D015331:Cohort Studies; D005260:Female; D006801:Humans; D058725:Peripartum Period; D011247:Pregnancy; D011250:Pregnancy Complications, Hematologic / Q000175:diagnosis / Q000453:epidemiology / Q000209:etiology*; D012189:Retrospective Studies; D018570:Risk Assessment; D012307:Risk Factors; D014592:Uterine Hemorrhage / Q000175:diagnosis / Q000453:epidemiology / Q000209:etiology*; D055815:Young Adult