The Committee on Educational Bulletins of the American College of Obstetricians and Gynecologists (ACOG) has released a report on the management of postpartum hemorrhage (Educational Bulletin No. 243). The report discusses the causes and management of postpartum hemorrhage.
The following is a summary of the ACOG report. The report begins by noting three factors that should be considered with regard to postpartum hemorrhage. First, blood loss is often underestimated by as much as 30 to 50 percent. Second, the expansion in blood volume that occurs during pregnancy compensates for normal blood loss at delivery, but this expansion occurs to a lesser degree in patients with preeclampsia. These patients have greater blood loss at delivery than do normotensive patients. Third, postpartum hemorrhage is likely to occur in subsequent pregnancies.
Risk Factors and Causes of Postpartum Hemorrhage
According to the ACOG report, the most common causes of postpartum hemorrhage are uterine atony and lacerations of the vagina and cervix. Other causes of postpartum hemorrhage include retained placental fragments, lower genital tract lacerations, uterine rupture or inversion, placenta accreta and hereditary coagulopathy. Causes of late postpartum hemorrhage (from 24 hours to six weeks after delivery) include infection, placental site subinvolution, retained placental fragments and hereditary coagulopathy.
Risk factors for uterine atony include uterine overdistention secondary to hydramnios, multiple gestation, use of oxytocin, fetal macrosomia, high parity, rapid or prolonged labor, intra-amniotic infection and use of uterine-relaxing agents. Predisposing factors for placenta accreta, which occurs in one of 2,500 deliveries, are previous puerperal curettage, cesarean delivery, hysterotomy, placenta previa and high parity. According to the report, the risk of placenta accreta may be 25 percent or higher in the presence of placenta previa and one or more previous cesarean delivery scars.
The report states that uterine rupture occurs in approximately one of 2,000 deliveries. Previous uterine surgery, particularly deep myomectomy or transfundal cesarean delivery, is a significant risk factor for uterine rupture and postpartum hemorrhage. Other risk factors include obstructed labor, multiple gestations, abnormal fetal lie and high parity.
Risk factors for hemorrhage at the time of cesarean delivery include preeclampsia, disorders of active labor, a history of previous hemorrhage, obesity, use of general anesthesia and intra-amniotic infection.
Management of Postpartum Hemorrhage
The algorithm on page 1004 summarizes the management of postpartum hemorrhage. The report states that adequate intravascular access should be obtained in women who have significant risk factors for postpartum hemorrhage. In the event of hemorrhage, supplemental oxygen should be administered to enhance cellular oxygen delivery and an indwelling urinary catheter should be inserted to facilitate assessment of intravascular volume resuscitation by monitoring urine output. Initial laboratory evaluation includes a complete blood count with platelet concentration. Blood type with antibody screen should be performed if it was not previously obtained. Fibrinogen, fibrin split products, prothrombin time and partial thromboplastin time should be measured.
Uterine atony should be initially managed by bimanual uterine massage and compression. Intravenous oxytocin, 10 to 40 U intravenously by continuous infusion, should be administered. Other uterotonic agents include methylergonovine and prostaglandin derivatives (15-methyl prostaglandin F2a). According to the report, prostaglandin derivatives are associated with success rates of 88 percent when used alone and 95 percent when used in combination with other oxytocic agents. Methylergonovine may be administered in a dosage of 0.2 mg intramuscularly every two to four hours. This agent is contraindicated in the presence of hypertensive disease states because of the severe hypertension that may develop secondary to vasoconstriction induced by the agent. The administration of 15-Methyl prostaglandin F2a may be given in a dosage of 0.25 mg intramuscularly every 15 to 90 minutes (no more than eight doses). This prostaglandin agent may also be given by intramyometrial injection at cesarean delivery or transabdominally after vaginal delivery. Prostaglandin E2 may cause vasodilatation and exacerbation of hypotension, therefore 15-Methyl prostaglandin F2a is preferred.
Surgical intervention is undertaken for direct indications, such as uterine curettage for suspected retained placental tissue, or for hemostasis if medical therapy fails. Obstetric lacerations are repaired by placing the initial suture above the apex of the laceration to control retracted arteries. Uterine artery ligation may be performed at laparotomy. Hypogastric artery ligation may be performed to reduce the arterial pulse pressure to pelvic organs. According to the report, hypogastric artery ligation is technically difficult and is successful in fewer than one half of patients. This intervention is increasingly being replaced by other forms of management. The most common indications for emergency hysterectomy include uterine atony, placenta accreta, uterine rupture, extension of a low transverse uterine incision and leiomyomata.
For more information on ACOG educational bulletins and committee opinions, contact ACOG at 409 12th St., S.W., Washington, D.C. 20090-6920; telephone: 800-762-2264.