Estimated versus measured blood loss during dilation and evacuation: an observational study.

Objective: To compare estimated versus measured blood loss at the time of dilation and evacuation (D&E).

Study Design: We measured blood loss for all D&E procedures between 16 and 24 weeks at one abortion clinic over 9 months. We weighed all blood-containing items and measured blood captured in the D&E tray. Providers recorded estimated blood loss before weighing or measuring blood. We compared median measured blood loss (MBL) and estimated blood loss (EBL) for each gestational week.

Results: We measured blood loss in 371 of the 534 D&Es in the study period; we excluded 163 procedures because of failure to measure blood loss or contamination with amniotic fluid. Included and excluded procedures had similar median EBLs. Median EBL differed significantly from MBL for each week gestation from 16 to 24 weeks (p≤.001 for all comparisons); MBL was approximately twice as high as EBL for each gestational week. EBL and MBL increased with increasing gestation, as did the difference between EBL and MBL.

Conclusion: Providers consistently and significantly underestimate blood loss at the time of D&E. D&E providers may want to consider using a new heuristic for estimating blood loss.

Implications: Providers significantly underestimate blood loss at the time of D&E. Future research should confirm these findings (particularly at 22-24 weeks gestation), evaluate the efficacy of interventions to improve estimations of blood loss, and determine best practices for decreasing blood loss.