5.1 Background

In this stage of labour placental separation and expulsion take place; for the mother the main risks are haemorrhage during or after separation of the placenta, and retention of the placenta. Postpartum haemorrhage is one of the main causes of maternal mortality; the large majority of these cases occur in developing countries (Kwast 1991). The incidence of postpartum haemorrhage and retention of the placenta is increased if predisposing factors are present, such as multiple pregnancy or polyhydramnios, and complicated labour: augmentation of labour, obstructed labour, or vaginal operative delivery (Gilbert et al 1987). Postpartum haemorrhage and placental retention also occur more frequently if these complications were present in the obstetric history of the woman (Doran et al 1955, Hall et al 1987, WHO 1989). To a certain extent therefore it is possible to select during pregnancy and in the course of labour those women with an increased risk of complications in the third stage. But even in low-risk pregnancies and after an uneventful first and second stage of labour serious haemorrhage and/or placental retention may sometimes occur. The management of the third stage may influence the incidence of these complications, and the amount of blood lost. Several measures aiming at the prevention of complications have been proposed, have been tested in randomized trials and are discussed below.