Uterine Atony: The Leading Cause of Postpartum HaemorrhageAfter birth, your uterus is supposed to contract firmly to stop bleeding from the area where the placenta was attached. When it doesn’t, blood vessels remain open, and heavy bleeding can begin within minutes. This failure of the uterus to contract is called uterine atony, the single most common cause of postpartum haemorrhage (PPH). Recognising its warning signs early and responding quickly can mean the difference between a routine recovery and a life-threatening emergency.