title: Visually estimated and calculated blood loss in vaginal and cesarean delivery.
abstract: OBJECTIVE
  The objective of the study was to compare visually estimated blood loss (vEBL) with calculated estimated blood loss (cEBL) according to mode of delivery and degree of perineal laceration.
  
  
  METHODS
  Pre- and postdelivery hematocrit (HCT) and other variables including vEBL were prospectively recorded into an obstetrical database between January and September 2005. The cEBL was derived by multiplying the calculated pregnancy blood volume (0.75 x {[maternal height (inches) x 50] + [maternal weight in pounds x 25]}) by percent of blood volume lost ({predelivery HCT - postdelivery HCT}/predelivery HCT). cEBL and vEBL were compared according to mode of delivery and degree of perineal laceration.
  
  
  RESULTS
  There were 677 subjects with complete data. vEBL was statistically different from cEBL between each degree of laceration and between all modes of delivery, demonstrating an underestimation of vEBL with increasing cEBL.
  
  
  CONCLUSIONS
  Improved methods for calculating blood loss include the use of a modified version of the formula used for pregnancy blood volume calculation.
authors.affiliation: Department of Obstetrics and Gynecology, Louisiana State University Health Sciences Center, New Orleans, LA 75390-9032, USA. istaff@parknet.pmh.org
authors.forename: Irene
authors.initials: I
authors.lastname: Stafford
authors.forename: Gary A
authors.initials: GA
authors.lastname: Dildy
authors.forename: Steven L
authors.initials: SL
authors.lastname: Clark
authors.forename: Michael A
authors.initials: MA
authors.lastname: Belfort
mesh_terms: D001810:Blood Volume; D002585:Cesarean Section; D036861:Delivery, Obstetric / Q000379:methods*; D005260:Female; D006400:Hematocrit; D006801:Humans; D022125:Lacerations; D010502:Perineum / Q000293:injuries; D006473:Postpartum Hemorrhage / Q000175:diagnosis; D011247:Pregnancy; D011446:Prospective Studies; D014592:Uterine Hemorrhage / Q000175:diagnosis*