Risk factors for postpartum haemorrhage in twin pregnancies and haemorrhage severity

This study evaluated risk factors for postpartum haemorrhage (PPH) in twin pregnancies, particularly factors associated with major PPH (blood loss of >1000 mL), to facilitate identification of high-risk twin pregnancies.

This retrospective cohort study included all women with twin pregnancies who delivered at a tertiary obstetric unit in Hong Kong from 2009 to 2018 and experienced PPH (blood loss of ≥500 mL). Postpartum haemorrhage was classified using three thresholds for blood loss volume: ≥500 mL (all PPH), >1000 mL (major PPH), and >1500 mL (severe PPH). Risk factors for each threshold of PPH were analysed.

In total, there were 680 twin pregnancies. The overall incidence of all PPH (≥500 mL) in this cohort was 27.8%, including minor PPH (500-1000 mL, 20.1%), major but not severe PPH (1001-1500 mL, 4.4%), and severe PPH (>1500 mL, 3.2%). Logistic regression analysis showed that general anaesthesia and the use of oxytocin were significant risk factors for all PPH (≥500 mL); general anaesthesia, in vitro fertilisation, antepartum haemorrhage, placental abruption, and placenta praevia were significant risk factors for major PPH (>1000 mL); in vitro fertilisation, placenta praevia, and obesity were significant risk factors for severe PPH (>1500 mL).

Women with twin pregnancies who have obesity, conception by in vitro fertilisation, or placenta praevia exhibit a high risk of severe PPH. They should deliver in obstetric units with readily available blood product transfusions and the appropriate expertise for prompt management of severe PPH.