Academic journal article Issues in Law & Medicine

Is Misoprostol Equivalent to Oxytocin for Postpartum Hemorrhage?

Academic journal article Issues in Law & Medicine

Is Misoprostol Equivalent to Oxytocin for Postpartum Hemorrhage?

Article excerpt

The Problem of Postpartum Hemorrhage

Postpartum hemorrhage (PPH) is the leading cause of pregnancy-related death in developed and developing countries, followed by high blood pressure in pregnancy, anemia, infection, and malaria and dengue infection. PPH complicates 6-10 percent of all births, is estimated to be responsible for approximately 1/4 - 1/3 of all maternal deaths, and has a case fatality rate of PA.1 In developing countries the risk of death from PPH is estimated to be 1:100 or higher.2 PPH is estimated to be responsible for 31% of maternal deaths in Asia, 34% in Africa, and 21% in Latin America and the Caribbean.5

Postpartum hemorrhage is defined as blood loss > 500 mL in the immediate postpartum period (1st 24 hrs) after vaginal or cesarean delivery (this paper will focus on PPH after vaginal delivery); other criteria include a decrease in hematocrit (blood count) or need for transfusion. PPH can occur immediately after birth or, perhaps more commonly, over the first 24 hours post-delivery, due to inadequate monitoring of bleeding and inattention to uterine massage in the recent parturient.

Cardiovascular Adaptation in Pregnancy and Mechanisms of Postpartum Hemostasis

A remarkable set of vascular, renal and coagulation system adaptations occur in pregnant women, which appear to protect against the consequences of PPH. Plasma volume begins to increase very early in pregnancy and increases until 28-34 weeks, with a parallel increase in blood volume. The total plasma volume at term is approximately 4.7-5.2 liters4 while blood volume is 100 mlVkg, or approximately 6.5 liters in a 65 kg woman.5 Salt retention and fluid redistribution occur during pregnancy, with an increase in extravascular fluid. As a result of increased red blood cell synthesis, red blood cell mass increases by 17-40% and the total blood volume is increased 45% over non-pregnant values. Cardiac output and heart rate increase while blood pressure de- creases until mid-pregnancy, when the latter begins to increase.6 Serum levels of clotting factors increase dramatically during pregnancy.

For adequate hemostasis to occur after delivery, contraction of uterine smooth muscle is required, which enables the uterus to stop bleeding during the third stage of labor (from birth of the neonate to placental separation and delivery of the placenta). Placental separation and expulsion occur in 3 stages. The first stage involves contraction of the uterus, followed by placental separation, detachment, and expulsion. Hemostasis occurs with myométrial contraction and compression of maternal vessels, spiral artery spasm and constriction, and transient activation of the coagulation system. In contrast, inadequate uterine contraction leads to uterine atony, where the uterus is slack and non-contracted. Uterine atony is responsible for an estimated 70% of cases of PPH.7 Thus, factors which predispose to uterine muscle fatigue or which interfere with uterine contraction are associated with postpartum hemorrhage.

Among the most common patient risk factors for PPH include anemia, grand multiparity (where a woman has given birth 5 or more times), long labor, twin gestation, large baby, genital lacerations, and retained clot or placenta. Of these, one of the most important risk factors is antenatal anemia, which increases mortality risk because blood loss which would be readily tolerated in a non-anemic woman can be symptomatic or fatal in a severely anemic woman. Another, often unrecognized source of blood loss is genital lacerations, which cause bleeding which cannot be controlled by increasing uterine contractions. Among the most common health system risk factors for PPH-related morbidity and mortality are lack of prenatal care, inadequate management of the second and third stage of labor, inadequate postpartum care, lack of access to health care facilities, and non-availability of emergency obstetrical services, including intensive care, transfusion and surgery. …

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