This systematic review concluded that the use of carbetocin during CD is associated with less blood loss during 1st 24 h after the operation (high evidence), reduced the incidence of PPH (high evidence), the hemoglobin drop (moderate evidence), the need for additional uterotonic agents (high evidence), and blood transfusion (high evidence) when compared to oxytocin without increase in adverse effects. This evidence concerns the gene OXT and pulmonary arterial hypertension.