[Epidemiology of post-partum haemorrhage]

To synthesize the available evidence regarding the incidence, causes, risk factors of post-partum haemorrhage (PPH) and the associated maternal morbidity.

Consultation of the Medline database and of national reports on maternal mortality.

PPH is defined as a post-partum blood loss≥500mL, and severe PPH as a post-partum blood loss≥1000mL, whatever the delivery route. In population-based studies, the incidence of PPH is around 5% of deliveries when blood loss is not precisely assessed and around 10% when it is. The incidence of severe PPH is around 2%. Uterine atony if the main cause of PPH. Maternal mortality due to obstetric haemorrhage has decreased in France (currently 1.6 death/100,000 live births) but remained the first cause of maternal death (16%) and the most avoidable (80%). In high-resource countries, PPH is the main cause of acute severe maternal morbidity, and of pregnancy-related ICU admissions. In addition to the direct consequences of acute hypovolemia, PPH exposes the women to the complications of transfusion, of intensive care and to infertility in case of hysterectomy. The main risk factors for PPH are factors of uterine atony, but they are globally poorly predictive.

PPH is the principal cause of severe maternal morbidity, most often due to uterine atony. Risk factors related to components of care during labor and delivery are amenable to change, and the assessment of their risks-benefits balance should take into account the associated risk of PPH.