title: Blood transfusion and cesarean delivery.
abstract: OBJECTIVE
  To evaluate risks for intraoperative or postoperative packed red blood cell transfusion in women who underwent cesarean delivery.
  
  
  METHODS
  This was a 19-university prospective observational study. All primary cesarean deliveries from January 1, 1999, to December 31, 2000, and all repeat cesareans from January 1, 1999, to December 31, 2002, were included. Trained, certified research nurses performed systematic data abstraction. Primary and repeat cesarean deliveries were analyzed separately. Univariable analyses were used to inform multivariable analyses.
  
  
  RESULTS
  A total of 23,486 women underwent primary cesarean delivery, of whom 762 (3.2%) were transfused (median 2 units, 25th% to 75th% 2-3 units). A total of 33,683 women underwent repeat [corrected] cesarean delivery, and 735 (2.2%) were transfused (median 2 units, 25th% to 75th% 2-4 units). Among primary cesareans, general anesthesia (odds ratio [OR] 4.2, 95% confidence interval [CI] 3.5-5.0), placenta previa (OR 4.8, CI 3.5-6.5) and severe (hematocrit less than 25%) preoperative anemia (OR 17.0, CI 12.4-23.3) increased the odds of transfusion. Among repeat cesareans, the risk was increased by general anesthesia (OR 7.2, CI 5.9-8.7), a history of five or more prior cesareans (OR 7.6, CI 4.0-14.3), placenta previa (OR 15.9, CI 12.0-21.0), and severe preoperative anemia (OR 19.9, CI 14.5-27.2).
  
  
  CONCLUSIONS
  Overall, the risk of transfusion in association with cesarean is low. However, both severe preoperative maternal anemia and placenta previa are associated with markedly increased risks. The former argues for optimizing maternal antenatal iron status to avoid severe anemia and the latter for careful perioperative planning when previa complicates cesarean.
  
  
  METHODS
  II-2.
authors.affiliation: Department of Obstetrics, the University of Alabama at Birmingham, Birmingham, Alabama 35249-7333, USA. drouse@uab.edu
authors.forename: Dwight J
authors.initials: DJ
authors.lastname: Rouse
authors.forename: Cora
authors.initials: C
authors.lastname: MacPherson
authors.forename: Mark
authors.initials: M
authors.lastname: Landon
authors.forename: Michael W
authors.initials: MW
authors.lastname: Varner
authors.forename: Kenneth J
authors.initials: KJ
authors.lastname: Leveno
authors.forename: Atef H
authors.initials: AH
authors.lastname: Moawad
authors.forename: Catherine Y
authors.initials: CY
authors.lastname: Spong
authors.forename: Steve N
authors.initials: SN
authors.lastname: Caritis
authors.forename: Paul J
authors.initials: PJ
authors.lastname: Meis
authors.forename: Ronald J
authors.initials: RJ
authors.lastname: Wapner
authors.forename: Yoram
authors.initials: Y
authors.lastname: Sorokin
authors.forename: Menachem
authors.initials: M
authors.lastname: Miodovnik
authors.forename: Marshall
authors.initials: M
authors.lastname: Carpenter
authors.forename: Alan M
authors.initials: AM
authors.lastname: Peaceman
authors.forename: Mary Jo
authors.initials: MJ
authors.lastname: O'Sullivan
authors.forename: Baha M
authors.initials: BM
authors.lastname: Sibai
authors.forename: Oded
authors.initials: O
authors.lastname: Langer
authors.forename: John M
authors.initials: JM
authors.lastname: Thorp
authors.forename: Susan M
authors.initials: SM
authors.lastname: Ramin
authors.forename: Brian M
authors.initials: BM
authors.lastname: Mercer
mesh_terms: D000740:Anemia / Q000150:complications* / Q000628:therapy; D016063:Blood Loss, Surgical; D001803:Blood Transfusion / Q000706:statistics & numerical data*; D002585:Cesarean Section / Q000009:adverse effects*; D017604:Cesarean Section, Repeat / Q000009:adverse effects; D005260:Female; D006801:Humans; D016015:Logistic Models; D015999:Multivariate Analysis; D010923:Placenta Previa / Q000503:physiopathology*; D006473:Postpartum Hemorrhage / Q000628:therapy*; D011247:Pregnancy; D011250:Pregnancy Complications, Hematologic; D011446:Prospective Studies; D018570:Risk Assessment