Precise estimation of postpartum haemorrhage: Difficulties and importance

Abstract

The accepted definition of postpartum haemorrhage is an estimated blood loss of at least 500 ml. after vaginal delivery. Estimation of blood loss is often unreliable, for few attendants have a clear appreciation of the appearance of 500 ml. of blood soaked into linen and the other accoutrements of delivery. Because of the failure to recognize the extent of haemorrhage, its true importance in maternal morbidity and mortality tends to be missed. Several methods have been used in attempts to measure blood loss accurately. Gatch and Little (1924) extracted haemoglobin and measured it as acid haematin by photometric comparison with a series of acid haematin solutions prepared by diluting the patient's venous blood. Pilcher and Sheard (1937) used the spectrophotometer to measure oxy haemoglobin concentrations. Coller et al. (1944) compared preand post-delivery haemoglobin and plasma protein con centrations. Gahres et al. (1962) used chromium-51-labelled red cells to compare the red cell mass before and after delivery, while Spoerel and Heagy (1962) used radioiodinated serum albumin to compare plasma volumes before and after delivery. Murdoch (1958) attempted complete collections in calibrated receptacles. The aim of the present investigation was to measure the amount of bleeding at vaginal delivery. In order to prevent confusion the estimate made by the attendant will be referred to as the recorded blood loss. The loss determined subse quently by calculation, using the washing-machine extraction method, is referred to as the measured loss.