Uterotonics Using to Reduce Bleeding at Cesarean Section

Overview

Postpartum haemorrhage continues to be a leading cause of maternal morbidity and mortality worldwide and that is according to the estimates of the World Health Organization in 1998. Average blood loss during delivery progressively increases with the type of delivery, vaginal delivery (500 ml), cesarean section (1000 ml) and emergency hysterectomy (3500 ml) of blood. A reduction of operative blood loss at cesarean section has a great benefit to the patients in terms of decreased postoperative morbidity and a decrease in risks associated with blood transfusions. The routine use of oxytocin is associated with a significant reduction in the occurrence of postpartum hemorrhage. Excessive blood loss as estimated by a 10% drop in the hematocrit value postdelivery or by need for blood transfusion, occurs in approximately 4% of vaginal deliveries and 6% of cesarean births. Although many delivery units use oxytocin as the first line agent to prevent uterine atony at cesarean section, it may not be the ideal agent for prevention of postpartum haemorrhage especially in compromised patients with preeclampsia, cardiac disease or prolonged labor. Oxytocin and specifically its preservative chlorobutanol increases the heart rate and has negative inotropic, antiplatelet and antidiuretic effects. Misoprostol, a prostaglandin E1 analogue, has been shown in many studies to be an effective myometrial stimulant of the pregnant uterus which binds to prostanoid receptors. Misoprostol administration, either by oral or rectal route, has been shown to be effective in prevention of postpartum haemorrhage and is considered as an effective alternative to other conventional oxytocics especially in developing countries as it is cheap and thermostable. Pharmacokinetic studies suggested that the bioavailability of misoprostol after sublingual administration was higher than those after oral or vaginal administration. A few studies are now available for the use of sublingual misoprostol in the prevention of postpartum haemorrhage following vaginal delivery and have reported it as an effective and convenient route of administration. However, none of the studies conducted so far have evaluated the response of sublingual misoprostol for prevention of postpartum haemorrhage during cesarean section.