Measurement of blood loss: review of the literature.

It is important to recognize excessive blood loss during childbirth, which is a significant cause of morbidity and mortality. This article reviews methods to measure blood loss that could be used during childbirth. PubMed, CINAHL, and MEDLINE databases were searched using the phrases "blood loss" and "measurement." The bibliographies of publications were scanned for applicable references. A total of 46 publications are included in this review. The methods used to measure blood loss are categorized into visual estimation, direct measurement, gravimetric, photometry, and miscellaneous. Methods are described and compared. A combination of direct measurement and gravimetric methods are the most practical. Photometry is the most precise, but also the most expensive and complex to use. A variety of miscellaneous methods are presented, but none is a practical or reliable method. Visual estimation of blood loss is so inaccurate that its continued use in practice is questionable and it should not be used in research to evaluate treatment. Copyright 2010 American College of Nurse-Midwives. Published by Elsevier Inc. All rights reserved.