The prevention of postpartum hemorrhage is crucial and oxytocin remains the first-line drug, but it must be used with utmost care, since it can lead to systemic hypotension and reflex tachycardia, which may cause an increase in the pulmonary arterial pressure.[7] Women with PAH are generally not recommended to breastfeed after delivery. The gene discussed is OXT; the disease is pulmonary arterial hypertension.