Objectives: This study was to report the incidence of severe maternal morbidity associated with hypertensive disorders of pregnancy in the United States.
Study design: We used data from the National Hospital Discharge Survey, a nationally representative sample of discharge records, from 1988 to 1997. The database consisted of approximately 300,000 deliveries, which represented 39 million births during the 10-year period.
Results: The overall incidence of hypertensive disorders in pregnancy was 5.9% [95% confidence interval (CI): 5.2 to 6.5%]. Eclampsia was reported at 1.0 per 1,000 deliveries (95% CI: 0.8 to 1.2). The incidence of eclampsia, severe preeclampsia, and superimposed preeclampsia remained unchanged during the 10-year period. Women with preeclampsia and eclampsia had a 3- to 25-fold increased risk of severe complications, such as abruptio placentae, thrombocytopenia, disseminated intravascular coagulation, pulmonary edema, and aspiration pneumonia. More than half of women with preeclampsia and eclampsia had cesarean delivery. African American women not only had higher incidence of hypertensive disorders in pregnancy but also tended to have a greater risk for most severe complications. Preeclamptic and eclamptic women younger than 20 years or older than 35 years had substantially higher morbidity.
Conclusion: Preeclampsia and eclampsia carry a high risk for severe maternal morbidity. Compared to Caucasians, African Americans have higher incidence of hypertensive disorders in pregnancy and suffer from more severe complications.