Post-partum haemorrhage - more common than you think

Post-partum haemorrhage (PPH) occurs in 5% to 15% of all deliveries and is responsible worldwide for a maternal mortality rate of between 25% to 33%.

There are four principal causes of PPH:
• Uterine atony (or loss of tone to the uterus), which contributes to about 80% of cases;
• Retained placental tissue;
• Trauma or tears to the uterus, cervix or vagina; and
• Pre-existing or acquired coagulopathy.

A simpler method to understand the underlying causes of PPH is to think in terms of the four Ts: Tone (uterine atony), Trauma (uterine, cervical or vaginal injury), Tissue (retained placenta) and Thrombin (coagulopathy).

PPH is defined as blood loss of 500 mL or more, and severe PPH as 1000 mL or more, in the third stage of labour. Active management of the third stage of labour has been proven to be effective in the prevention of PPH and has three components: the use of a uterotonic agent, early cord clamping and controlled cord traction.

Active management with uterotonic agents, including oxytocin, ergotamine and prostaglandins, has proven effective in reducing the incidence of PPH. Oxytocin is an endogenous hormone responsible for effective postpartum haemostasis. It is currently the mainstay of therapeutic intervention in the active management of the third stage of labour, to maintain uterine tone and prevent PPH. More recently, carbetocin, a long acting oxytocin analogue, has become available in Australia for use in preventing PPH in patients undergoing elective caesarean section.Carbetocin is administered as a single intravenous 100 µg injection.