The prophylactic administration of oxytocin, either alone or as part of active management of the third stage of labor (AMTSL), has been proven effective to prevent PPH and is strongly recommended as standard care in all deliveries.[6–8] Although there is strong evidence showing the efficacy of oxytocin/AMTSL in preventing up to 60% of PPH cases, its use in real-life settings and thus its effectiveness is suboptimal and heterogeneous. This evidence concerns the gene OXT and pulmonary arterial hypertension.