Medicina

ACOG PRACTICE BULLETIN
CLINICAL MANAGEMENT GUIDELINES FOR OBSTETRICIAN–GYNECOLOGISTS NUMBER 76, OCTOBER 2006
(Replaces Committee Opinion Number 266, January 2002)

Postpartum Hemorrhage
This Practice Bulletin was developed by the ACOG Committee on Practice Bulletins— Obstetrics with the assistance of William N. P. Herbert, MD, and Carolyn M. Zelop, MD. The information is designed to aidpractitioners in making decisions about appropriate obstetric and gynecologic care. These guidelines should not be construed as dictating an exclusive course of treatment or procedure. Variations in practice may be warranted based on the needs of the individual patient, resources, and limitations unique to the institution or type of practice. Severe bleeding is the single most significant cause ofmaternal death worldwide. More than half of all maternal deaths occur within 24 hours of delivery, most commonly from excessive bleeding. It is estimated that, worldwide, 140,000 women die of postpartum hemorrhage each year—one every 4 minutes (1). In addition to death, serious morbidity may follow postpartum hemorrhage. Sequelae include adult respiratory distress syndrome, coagulopathy, shock, lossof fertility, and pituitary necrosis (Sheehan syndrome). Although many risk factors have been associated with postpartum hemorrhage, it often occurs without warning. All obstetric units and practitioners must have the facilities, personnel, and equipment in place to manage this emergency properly. Clinical drills to enhance the management of maternal hemorrhage have been recommended by the JointCommission on Accreditation of Healthcare Organizations (2). The purpose of this bulletin is to review the etiology, evaluation, and management of postpartum hemorrhage.

Background
The physiologic changes over the course of pregnancy, including a plasma volume increase of approximately 40% and a red cell mass increase of approximately 25%, occur in anticipation of the blood loss that will occurat delivery (3). There is no single, satisfactory definition of postpartum hemorrhage. An estimated blood loss in excess of 500 mL following a vaginal birth or a loss of greater than 1,000 mL following cesarean birth often has been used for the diagnosis, but the average volume of blood lost at delivery can approach these amounts (4, 5). Estimates of blood loss at delivery are notoriouslyinaccurate, with significant underreporting being the rule. Limited instruction on estimating blood loss has been shown to improve the accuracy of such estimates (6). Also, a decline in hematocrit levels of 10% has been used to define postpartum hemorrhage, but determinations of hemoglobin or hematocrit concentrations may not reflect the current hematologic status (7). Hypotension, dizziness, pal-VOL. 108, NO. 4, OCTOBER 2006

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lor, and oliguria do not occur until blood loss is substantial—10% or more of total blood volume (8). Postpartum hemorrhage generally is classified as primary or secondary, with primary hemorrhage occurring within the first 24 hours of delivery and secondary hemorrhage occurring between 24 hours and 6–12 weeks postpartum. Primarypostpartum hemorrhage, which occurs in 4–6% of pregnancies, is caused by uterine atony in 80% or more of cases (7). Other etiologies are shown in the box “Etiology of Postpartum Hemorrhage,” with risk factors for excessive bleeding listed in the box “Risk Factors for Postpartum Hemorrhage.” If excessive blood loss is ongoing, concurrent evaluation and management are necessary. A number of generalmedical supportive measures may be instituted, including provision of ample intravenous access; crystalloid infusion; blood bank notification that blood products may be necessary; prompt communication with anesthesiology, nursing, and obstetrician–gynecologists; and blood collection for baseline laboratory determinations. When treating postpartum hemorrhage, it is necessary to balance the use of...