A Comparison of Visual Estimate versus Calculated Estimate of Blood Loss at Vaginal Delivery

Aims: To compare blood loss following vaginal delivery by two different methods: visually estimated blood loss (vEBL) and calculated estimate of blood loss (cEBL).

Study Design: Postpartum blood loss was analyzed during 2 different time frames: 1. Traditional estimation (vEBL) of blood loss and 2. Following training, with the use of a systematic method (cEBL).

Place and Duration of Study: Department of Labor and Delivery at Maricopa Medical Center in Phoenix, Arizona. Charts were reviewed from September and October 2009 and from September 2010.

Methodology: This was a retrospective cohort study in which blood loss was compared using two different methods. Traditional physician estimate of blood loss at vaginal delivery, “vEBL” was compared to a more formal determination of blood loss “cEBL” - calculated blood loss.

Results: The cEBL subjects (mean age 28.0+/-6.6) were significantly older than the vEBL subjects (mean age 25.4+/-5.8). The two groups were otherwise similar. Mean blood loss was compared across the two methods using Analysis of Variance. Mean blood loss was 324 for the cEBL group, and 309 for the vEBL group (F(1,192)=0.76, p=.385). Although the difference in mean blood loss was not statistically significant, the variance of the cEBL method was significantly larger (P<.0005). 2/94 (2.1%) of patients in the vEBL group were noted to have blood loss ≥500cc; 11/100 (11%) of patients in the cEBL group were noted to have blood loss ≥500cc.

Conclusion: The variance for the cEBL method was significantly greater than in the vEBL group, suggesting that postpartum hemorrhage may be diagnosed sooner with this method. As calculation of blood loss postpartum is increasingly endorsed we recommend further study to determine the typical range for blood loss with measurement via this technique.