What is the issue?
While postpartum haemorrhage (PPH) is one of the leading causes of maternal death worldwide, it mostly occurs in low-income countries. It frequently occurs during the third stage of labour, the period of time from delivery of the baby to the expulsion of the placenta and membranes. During this period, the birth attendant evaluates how much blood the mother has lost.
Why is this important?
There is always some blood loss after the birth of a baby, but when this loss is excessive, it is called PPH. Severe PPH can lead to poor health for the mother (maternal morbidity), and sometimes even death, particularly in low- and middle-income countries. If excessive blood loss is identified early, interventions to help stem the blood flow can be started sooner, and improve health outcomes for the mother. Therefore, it is important to find the best method to measure blood loss after birth; one that is practical in all birth settings, including those in low- to middle-income countries.
In many instances, the birth attendant assesses blood loss by looking at the amount of blood lost, and estimating its volume (visual estimation). While this method is not very accurate, it is available in all birth settings. In another method, the birth attendant places a shallow bedpan below the mother’s buttocks, and then weighs the collected blood, along with blood that has soaked into any pads and material. This is referred to as an indirect method. In one direct method that has been devised, a ‘calibrated delivery drape’ is placed under the mother’s buttocks and tied around her waist, with the calibrated funnel portion (that indicates how much blood she has lost) hanging down between her legs. Other methods are also available, such as dye dilutions and radioactive techniques, but these are not practical in many birth settings.
What evidence did we find?
We searched for evidence in February 2018, and found three randomised controlled trials, involving over 26,000 women. Two trials contributed data to our analyses; one study did not provide data for any of the outcomes of interest in this review. All of the trials took place in hospital settings. Two trials took place in India, the other was conducted in 13 different European countries. The trials examined different methods of estimating blood loss.
One trial (conducted in 13 European countries, involving over 25,000 women) compared the use of a calibrated drape (direct estimation) to visual estimation (indirect estimation). Moderate-quality evidence showed there was probably little or no difference between the methods for the risk of women developing serious conditions (e.g. failure to form clots, poor functioning of the liver, kidneys, and brain, admission to intensive care); their need for blood transfusion; the use of fluids to maintain their blood pressure; or the use of drugs to help their uterus contract to stop the bleeding. The trial did not report the number of women who had anaemia after birth, blood loss of at least 500 mL, or infection.
One trial (conducted in India, involving 900 women) compared the use of a calibrated drape (direct estimation) to weighing and measuring blood and blood-soaked materials (indirect method). High-quality evidence showed that calibrated drapes were better than measuring the blood and blood-soaked materials at detecting blood loss of at least 500 mL. Low-quality evidence showed there may be little or no difference between methods in the need for blood transfusion or fluids to maintain blood pressure. High-quality evidence showed little or no difference in the use of drugs to help the uterus contract in order to stop bleeding. The trial did not report the number of women who had anaemia after birth or infection, or the risk of developing serious conditions (such as failure to form clots, poor functioning of the liver, kidneys, and brain, or being admitted to intensive care).
What does this mean?
There was insufficient evidence to support the use of one method over another to estimate blood loss after vaginal birth. There is a need for high quality trials that measure important outcomes, such as those listed in this review.