The purpose of this study is to evaluate the effectiveness of two doses of carbetocin (50 mcg vs 100 mcg) in preventing uterine atony during elective cesarean section.

Postpartum hemorrhage is a major cause of mortality and morbidity in the world, and it is most often caused by uterine atony. To prevent this complication, uterotonic medication is used during elective cesarean section.

Carbetocin, a long-acting synthetic analogue of oxytocin, has been used for this purpose for many years. This medication has numerous side effects: hypotension, tachycardia, nausea, vomiting, chest pain, etc. Using a smaller dose of carbetocin might lower the incidence of these side effects, without compromising prevention of uterine atony in a low-risk group of patient.

Inclusion Criteria:

• ≥ 18 years old
• ≥ 37-week pregnancy
• singleton pregnancy
• elective cesarean section with a low transverse incision
• ASA I or II

Exclusion Criteria:

• Personal history of uterine atony or postpartum hemorrhage
• Abnormal placental implantation (known or suspected)
• > 3 cesarean sections in the past
• Personal history of a classic uterine incision
• Estimated fetal weight > 4500g
• Hemoglobin < 100 g/L
• Regular use of tocolytic drugs
• Cesarean section under general anesthesia
• Known allergy to carbetocin
• Refusal
• Inability to obtain informed consent