Pregnancy-Related Mortality in the United States, 2011–2013

TLDR

The study updated national pregnancy‑related mortality estimates for 2011‑2013 and examined characteristics and causes of deaths, comparing 10 cause‑of‑death categories with earlier reports. Using observational data from the Pregnancy Mortality Surveillance System, the authors calculated mortality ratios by year, age, and race‑ethnicity and analyzed cause‑of‑death distributions by pregnancy outcome. The 2011‑2013 mortality ratio was 17.0 per 100,000 live births, rose with maternal age, and was 3.4 times higher among non‑Hispanic black women; cardiovascular conditions were the leading cause (15.5%), with overall cause distribution remaining stable but showing a shift from hemorrhage and hypertensive disorders toward cardiovascular and other medical conditions.

Abstract

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. 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. 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). The pregnancy-related mortality ratio and the distribution of the main causes of pregnancy-related mortality have been relatively stable in recent years.