Incidence and Risk Factors of Severe Obstetric Hemorrhage

Introduction

Severe obstetric hemorrhage is the most feared obstetric emergency that can occur to any woman at childbirth. If unattended, the hemorrhage can kill even a healthy woman within two hours [1, 2]. The Hemorrhage accounts for nearly one-quarter of all maternal deaths, and for almost half of all postpartum deaths in low-income countries [2–4]. Recent studies in high resource settings [5] including Canada [6], the USA [7], Australia [8], and the UK [9] indicate an unexpected and unexplained increase in obstetric hemorrhage over the last 10 years. Although maternal deaths are extremely rare in high resource settings, the morbidity associated with a severe hemorrhage is still a major problem [9–13]. Many more women survive but suffer serious illness as a result, not only from the effects of acute hypoperfusion and anemia, but also from the interventions that a severe hemorrhage may necessitate [14–16]. Severe obstetric hemorrhage is, however, the most preventable complication. Nonetheless, suboptimal obstetric care was identified in more than half the deaths due to hemorrhage [17, 18]. It is therefore suggested as a complementary indicator for the assessment of the quality of obstetric care [19, 20]. The aim of this article is to review the incidence, causes, and risk factors of severe obstetric hemorrhage.

Abstract

Severe obstetric hemorrhage is the main cause of severe maternal morbidity and mortality worldwide. The incidence of severe hemorrhage varies considerably, even among countries with high resource settings. Uterine atony is the main cause of severe obstetric hemorrhage, followed by retained placental tissues and trauma of the genital tract. Preexisting or acquired coagulopathy accounted for almost 1% of severe obstetric hemorrhage. The mode of delivery is the most important risk factor for severe obstetric hemorrhage, especially an emergency cesarean section (CS), followed by elective CS. Other important risk factors included multiple pregnancy, von Willebrand's disease, HELLP syndrome, anemia, macrosomia, cardiac disease, chorioamnionitis, induction, prolonged labor, and older age. Mothers with a history of unexplained severe obstetric hemorrhage should be investigated for preexisting or acquired bleeding disorders, and should receive conjoined care by a hematologist, obstetrician, and anesthesiologist during pregnancy and labor as well as in the postpartum period. Severe obstetric hemorrhage is a relatively frequent complication. Increasing knowledge of risk factors may contribute to reducing its incidence and impact. The findings call for reviewing labor management, as well as screening for different bleeding disorders.

Keywords

severe obstetric hemorrhage, risk factors, causes, coagulopathy, uterine atony