Maternal Mortality in the United States: Recent Trends, Current Status, and Future Considerations

Abstract

Rigorous studies carried out by the National Center for Health Statistics show that previously reported increases in maternal mortality rates in the United States were an artifact of changes in surveillance. The pregnancy checkbox, introduced in the revised 2003 death certificate and implemented by the states in a staggered manner, resulted in increased identification of maternal deaths and in reported maternal mortality rates. This Commentary summarizes the findings of the National Center for Health Statistics reports, describes temporal trends and the current status of maternal mortality in the United States, and discusses future concerns. Although the National Center for Health Statistics studies, based on recoding of death certificate information (after excluding information from the pregnancy checkbox), showed that crude maternal mortality rates did not change significantly between 2002 and 2018, age-adjusted analyses show a temporal reduction in the maternal mortality rate (21% decline, 95% CI 13-28). Specific causes of maternal death, which were not affected by the pregnancy checkbox, such as preeclampsia, showed substantial temporal declines. However, large racial disparities continue to exist: Non-Hispanic Black women had a 2.5-fold higher maternal mortality rate compared with non-Hispanic White women in 2018. This overview of maternal mortality underscores the need for better surveillance and more accurate identification of maternal deaths, improved clinical care, and expanded public health initiatives to address social determinants of health. Challenges with ascertaining maternal deaths notwithstanding, several causes of maternal death (unaffected by surveillance artifacts) show significant temporal declines, even though there remains substantial scope for preventing avoidable maternal death and reducing disparities.

Fig. 1.. Temporal trends in maternal deaths in the United States, 1993–2014, showing a small increase in maternal mortality with the introduction of International Classification of Diseases, Tenth Revision (ICD-10 codes) in 1999, and larger increases after the staggered adoption of the pregnancy checkbox on death certificates. Maternal mortality rates, including and excluding late maternal deaths (ICD-10 codes O96, O97) (A) and all maternal deaths, maternal deaths excluding late maternal deaths, deaths due to “Other specified pregnancy-related conditions” (O268), and deaths due to “other maternal diseases classifiable elsewhere” (O99) (B). Reprinted from Obstet Gynecol 2017;129:91‒100.

Joseph. Maternal Mortality in the United States. Obstet Gynecol 2021.

Fig. 2.. Temporal trends in maternal mortality due to selected causes of death, United States, 1999–2018. Maternal deaths due to chronic hypertension, preeclampsia, and gestational hypertension (A); maternal deaths due to diabetes mellitus, adherent placenta, and liver disorders (B); maternal deaths due to amniotic fluid embolism, blood clot embolism, and mental and central nervous system (CNS) disorders complicating pregnancy, childbirth, or the puerperium (C). Note that all rates are moving averages.

Joseph. Maternal Mortality in the United States. Obstet Gynecol 2021.

Fig. 3.. Maternal deaths within International Classification of Diseases, Tenth Revision (ICD-10) cause-of-death categories, United States, 2018. A. Maternal mortality rates (per million live births) within each ICD-10 cause-of-death category (all O chapter codes except those for late maternal death included). B. Cause-specific maternal mortality rates (per million live births) for specific causes of death of obstetric interest. Note that numbers in A represent cause-specific maternal mortality rates per million live births. The components of the pie chart are mutually exclusive and all-inclusive and sum to an overall maternal mortality rate of 17.4 per 100,000 live births. CNS, central nervous system.

Joseph. Maternal Mortality in the United States. Obstet Gynecol 2021.

Figure

No available caption