MediumO&GPostpartum haemorrhage due to uterine atonyau-amc
A 32-year-old woman has a vaginal birth complicated by postpartum haemorrhage with estimated blood loss of 900 mL due to uterine atony. She is haemodynamically stable after initial fluid resuscitation. According to postpartum haemorrhage prevention and management principles, what is the most appropriate first-line uterotonic drug?