Overview of maternal mortality in the United States.

Although dramatic improvements in pregnancy care and in general population health facilitated a dramatic decline in maternal mortality in the United States during the 20th century, women still die from complications of pregnancy. Moreover, rates appear to have increased during the early 21st century. This overview will provide context for understanding the problem of maternal mortality in the United States by outlining how maternal mortality rates are reported from National Vital Statistics data, and how pregnancy-related mortality ratios are reported from a national surveillance system. Trends and patterns in these deaths as well as emerging issues concerning causes of maternal deaths and the difficulty with interpreting trend data will be discussed.