Carbetocin vs Misoprostol for Postpartum Hemorrhage Prevention

Postpartum hemorrhage (PPH), most commonly caused by uterine atony, remains a major contributor to maternal morbidity and mortality. Women with established risk factors-such as grand multiparity, prior PPH, prolonged labor, fetal macrosomia, polyhydramnios, chorioamnionitis, or prolonged oxytocin exposure-are at particularly increased risk following vaginal delivery.

Active management of the third stage of labor using uterotonic medications is the cornerstone of PPH prevention. Oxytocin is widely used but has a short half-life, often requiring repeated dosing or continuous infusion. Carbetocin is a synthetic oxytocin analogue with a longer half-life and sustained uterotonic effect, which may offer improved prophylaxis against PPH. Misoprostol, a prostaglandin E1 analogue, is also commonly used due to its low cost, ease of administration, and stability, although it is associated with gastrointestinal and thermoregulatory side effects.

While carbetocin has demonstrated superiority over oxytocin in cesarean deliveries, evidence comparing carbetocin with misoprostol in high-risk vaginal deliveries is limited. This prospective, randomized, single-center study will enroll women at term with singleton pregnancies and predefined risk factors for postpartum hemorrhage. Participants will be randomized in a 1:1 ratio to receive either intravenous carbetocin (100 µg) or rectal misoprostol (1000 µg) with standard oxytocin after placental delivery.

The primary outcome is the occurrence of postpartum hemorrhage. Secondary outcomes include the need for additional uterotonic agents, blood transfusion, uterine revision or manual placental removal, changes in hemoglobin levels before and after delivery, duration of maternal hospitalization, and maternal adverse effects such as diarrhea, shivering, headache, and facial flushing.

This study aims to provide high-quality prospective data to guide the optimal prophylactic uterotonic strategy for women at increased risk of postpartum hemorrhage following vaginal delivery.

Inclusion criteria

• Women aged 18 years or older
• Singleton pregnancy
• Gestational age 37-42 weeks
• Cephalic presentation
• Vaginal delivery
• Presence of one or more risk factors for postpartum hemorrhage, including:
• Grand multiparity (≥5 previous deliveries)
• History of postpartum hemorrhage
• History of manual removal of placenta
• Estimated fetal weight ≥4,000 grams
• Polyhydramnios
• Chorioamnionitis
• Prolonged oxytocin use during labor (third augmentation cycle or more)
• Eligible for prophylactic uterotonic therapy after delivery
• Provided written informed consent

Exclusion criteria

• Multiple gestation
• Known major fetal anomalies
• Intrauterine fetal demise (IUFD)
• Contraindication to vaginal delivery
• Known hypersensitivity to carbetocin, misoprostol, or oxytocin
• Known coagulation disorders requiring alternative management
• Planned cesarean delivery
• Participation in another interventional study that may affect postpartum bleeding outcomes