ABSTRACT
Oxytocin has historically been the uterotonic of choice for postpartum hemorrhage prophylaxis, as it reduces blood loss and has fewer side effects compared with other agents such as ergot alkaloids and misoprostol. The third stage of labor involves separation of the placenta with capillary hemorrhage and shearing of the placental surface when the uterus contracts after delivery of the infant. Signs of separation include a gush of blood, cord lengthening, and the uterine fundus becoming more globular and firmer. Oxytocin binds to specific uterine receptors with immediate action, causing increasing strength and frequency of contractions. Ergot alkaloids cause sustained tonic contraction of uterine smooth muscle by stimulation of alpha-adrenergic myometrial receptors. Recent evidence suggests that numerous regimens of uterotonic agents, including oxytocin with ergot alkaloids, carbetocin alone, or oxytocin with misoprostol, are more effective at reducing blood loss at delivery than oxytocin alone.
