What is the optimal pharmacological management of retained placenta?

The third stage of labour is the period between childbirth and delivery of the placenta. It can be managed physiologically, with early cord clamping, cutting of the cord, and controlled cord traction, or it can be managed actively, with the addition of prophylactic oxytocics (oxytocin 10 IU intramuscularly). In the United Kingdom, the National Institute of Health and Care Excellence (NICE) defines the third stage of labour as prolonged if the placenta is retained after 30 minutes of active management or 60 minutes of physiological management.1 Retained placenta affects 0.1-3.3% of births, depending on the population studied.2 The incidence of retained placenta is rising because an increasing number of women with risk factors, including advancing maternal age and previous caesarean section, are giving birth.3 Retained placenta can result in severe maternal morbidity, including life threatening haemorrhage and sepsis.

Drugs, such as intraumbilical or intravenous oxytocin, are often used in the management of placental retention. Oxytocics cause myometrial contraction, which generates a shearing force that detaches the placenta from the uterine wall. However, after placental detachment, cervical constriction may trap the placenta within the uterus. Smooth muscle relaxants (such as glyceryl trinitrate) can release this entrapment and allow placental delivery. In practice, a variety of the drugs are used.

Despite active pharmacological management, if a retained placenta is not delivered, the placenta must be removed manually. This invasive surgical procedure physically removes the placenta from the uterine cavity and requires regional or general anaesthesia. The procedure can be complicated by haemorrhage, pain, infection, uterine inversion or perforation, and their …