Puerperal (postpartum) psychosis – the acute onset of a manic or psychotic episode shortly after childbirth – most commonly occurs in women with a bipolar disorder diathesis who have a vulnerability to a specific childbirth-related trigger. Women with bipolar disorder are at particularly high risk of puerperal psychosis, with a severe affective episode following between 25 and 50% of deliveries. Suicide is a leading cause of maternal death in the UK and it is clear that we must do more to identify and better manage women at high risk of illness related to childbirth. The clinical picture of puerperal psychosis can vary dramatically from hour to hour and can escalate quickly to a true psychiatric emergency. It is vital that clinical services identify women who are unwell and can respond quickly to the severity of illness, delivering treatment in the most appropriate setting for the mother and her baby.