Maternal mortality in the US before vs. during the COVID-19 pandemic

June 29, 2022
Change in maternal deaths during the pandemic may involve conditions directly related to COVID-19.

Given a 16.8% increase in overall US mortality in 2020, largely attributed to the COVID-19 pandemic, the National Center for Health Statistics (NCHS) examined the pandemic’s role in 2020 maternal death rates and reported an 18.4% increase in US maternal mortality (ie, death during pregnancy or within 42 days of pregnancy) between 2019 and 2020, according to a news release.

The relative increase was 44.4% among Hispanic, 25.7% among non-Hispanic Black, and 6.1% among non-Hispanic White women.

This study was published in the journal JAMA.

NCHS mortality and natality files from 2018 to 2020 were used to analyze maternal deaths based on underlying cause of death in accordance with NCHS guidelines. None of these codes exclusively identify COVID-19 (ICD-10 U07.1) as the cause even when COVID-19 was a factor in maternal death. Therefore, COVID-19 was ascertained as a secondary cause from the multiple causes-of-death section, consistent with other reports on excess mortality from COVID-19.

Deaths were stratified by month, and year of death was stratified into before (2018, 2019, and January-March [quarter 1] 2020) or during (April-December [quarters 2-4] 2020) the pandemic. Maternal mortality rates and percentages with a secondary COVID-19 code were compared by timing, race and ethnicity, and underlying cause (which were all included in NCHS data). Differences were assessed using a z test of proportions.

A total of 1588 maternal deaths (18.8 per 100 000 live births) occurred before the pandemic vs 684 deaths (25.1 per 100 000 live births) during the pandemic, a relative increase of 33.3%. Late maternal mortality increased by 41%. Absolute and relative changes were highest for Hispanic (8.9 per 100 000 live births and 74.2%, respectively) and non-Hispanic Black (16.8 per 100 000 live births and 40.2%) vs non-Hispanic White (2.9 per 100 000 live births and 17.2%) women. A secondary code for COVID-19 was listed in 14.9% (102 of 684) of maternal deaths in quarters 2 to 4, with 0% in quarter 1 of 2020. This percentage was highest among Hispanic women (32.1%), followed by non-Hispanic Black (12.9%) and non-Hispanic White (7.3%) women.

For underlying cause-of-death codes, the largest relative increase was among indirect causes (56.9%), specifically other viral diseases (2374.7%), diseases of the respiratory system (117.7%), and diseases of the circulatory system (72.1%). Relative increases in direct causes (27.7%) were mostly associated with diabetes in pregnancy (95.9%), hypertensive disorders (39.0%), and other specified pregnancy-related conditions (48.0%). COVID-19 was commonly listed as a secondary condition with other viral diseases (16 of 16 deaths [100%]) and diseases of the respiratory system (11 of 19 deaths [57.9%]). Almost half of those with a secondary code for COVID-19 (49 of 102) had a nonspecific code as the underlying cause.

In the US, maternal deaths increased substantially (33.3%) after March 2020, corresponding to COVID-19 onset, a figure higher than the 22% overall excess death estimate associated with the pandemic.  Increases were highest for Hispanic and non-Hispanic Black women. Change in maternal deaths during the pandemic may involve conditions directly related to COVID-19 (respiratory or viral infection) or conditions exacerbated by COVID-19 or other healthcare disruptions (diabetes or cardiovascular disease) but could not be discerned from the data.

Future studies of maternal death should examine the contribution of the pandemic to racial and ethnic disparities and should identify specific causes of maternal deaths overall and associated with COVID-19.

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