Objective: To update national population-level pregnancy-related mortality estimates and examine characteristics and causes of pregnancy-related deaths in the United States during 2011-2013.
Methods: We conducted an observational study using population-based data from the Pregnancy Mortality Surveillance System to calculate pregnancy-related mortality ratios by year, age group, and race-ethnicity groups. We explored 10 cause-of-death categories by pregnancy outcome during 2011-2013 and compared their distribution with those in our earlier reports since 1987.
Results: The 2011-2013 pregnancy-related mortality ratio was 17.0 deaths per 100,000 live births. Pregnancy-related mortality ratios increased with maternal age, and racial-ethnic disparities persisted with non-Hispanic black women having a 3.4 times higher mortality ratio than non-Hispanic white women. Among causes of pregnancy-related deaths, the following groups contributed more than 10%: cardiovascular conditions ranked first (15.5%) followed by other medical conditions often reflecting pre-existing illnesses (14.5%), infection (12.7%), hemorrhage (11.4%), and cardiomyopathy (11.0%). Relative to the most recent report of Pregnancy Mortality Surveillance System data for 2006-2010, the distribution of cause-of-death categories did not change considerably. However, compared with serial reports before 2006-2010, the contribution of hemorrhage, hypertensive disorders of pregnancy, and anesthesia complications declined, whereas that of cardiovascular and other medical conditions increased (population-level percentage comparison).
Conclusion: The pregnancy-related mortality ratio and the distribution of the main causes of pregnancy-related mortality have been relatively stable in recent years.