Pregnancy-related mortality in the United States, 1998 to 2005

Abstract

Objective: To estimate the risk of women dying from pregnancy complications in the United States and to examine the risk factors for and changes in the medical causes of these deaths.

Methods: De-identified copies of death certificates for women who died during or within 1 year of pregnancy and matching birth or fetal death certificates for 1998 through 2005 were received by the Pregnancy Mortality Surveillance System from the 50 states, New York City, and Washington, DC. Causes of death and factors associated with them were identified, and pregnancy-related mortality ratios (pregnancy-related deaths per 100,000 live births) were calculated.

Results: The aggregate pregnancy-related mortality ratio for the 8-year period was 14.5 per 100,000 live births, which is higher than any period in the previous 20 years of the Pregnancy Mortality Surveillance System. African-American women continued to have a three- to four-fold higher risk of pregnancy-related death. The proportion of deaths attributable to hemorrhage and hypertensive disorders declined from previous years, whereas the proportion from medical conditions, particularly cardiovascular, increased. Seven causes of death--hemorrhage, thrombotic pulmonary embolism, infection, hypertensive disorders of pregnancy, cardiomyopathy, cardiovascular conditions, and noncardiovascular medical conditions--each contributed 10% to 13% of deaths.

Conclusion: The reasons for the reported increase in pregnancy-related mortality are unclear; possible factors include an increase in the risk of women dying, changed coding with the International Classification of Diseases, 10th Revision, and the addition by states of pregnancy checkboxes to the death certificate. State-based maternal death reviews and maternal quality collaboratives have the potential to identify deaths, review the factors associated with them, and take action on the findings.