Considering that research on the risk of PPH after oxytocin exposure is generally restricted to the use of PPH prophylaxis and vaginal births, future controlled studies should evaluate whether administration of oxytocin in cesarean delivery is associated with a higher risk of PPH taking into account that labouring and non-labouring women may show a difference response to exogenous oxytocin. Here, OXT is linked to pulmonary arterial hypertension.