During the COVID-19 pandemic, the National Center for Health Statistics (NCHS) reported an 18.4% increase in maternal mortality in the United States. Overall, mortality in the United States increased by 16.8% during the pandemic, so the fact that maternal mortality increased even more merits further investigation.

A study, published this week in the Journal of the American Medical Associationexamined the role of the pandemic in maternal mortality rates in 2020. Investigators used NCHS death and birth records from 2018 to 2020. Mortalities were stratified by month, and years were stratified before the pandemic (2018, 2019, January-March 2020) and after the pandemic (April-December 2020).

Maternal mortality rates and percentages of deaths with COVID-19 as a secondary cause were compared by time, race, ethnicity and underlying cause.

A total of 1,588 maternal deaths (18.8 per 100,000 live births) occurred before the pandemic and 684 deaths (25.1 per 100,000) occurred during the pandemic, a relative increase of 33.3%. Late maternal deaths increased by 41%.

Disaggregated by ethnicity, maternal deaths during COVID-19 increased by 44.4% among Hispanic women, 25.7% among non-Hispanic black women, and 6.1% among non-Hispanic white women.

COVID-19 as a secondary cause of death was coded in 14.9% of maternal deaths in the second to fourth quarters of 2020. At 32.1%, this percentage was also highest among Hispanic women, followed by 12.9% among non-Hispanic black women and 7.3% among non-Hispanic white women.

The largest relative increase in causes of maternal death was from indirect causes (56.9%), with an increase of 2374.7% in other viral diseases, 117.7% in diseases of the respiratory system and 72. 1% of diseases of the circulatory system.

The 27.7% relative increase in direct causes was associated 95.9% with diabetes in pregnancy, 39.0% with hypertensive disorders, and 48.0% with other specified pregnancy-related conditions.

COVID-19 was listed as a secondary cause of death in 16/16 maternal deaths from other viral illnesses and 11/19 deaths from respiratory disease. Almost half of maternal deaths with COVID-19 as a secondary cause of death had an unspecific code listed as the primary cause of death.

Investigators concluded that maternal deaths in the United States increased by 33.3% after March 2020, which is greater than the overall mortality increase of 22% associated with the pandemic.

This increase in maternal mortality during the pandemic may be due to respiratory or viral conditions directly related to COVID-19, or to conditions exacerbated by COVID-19, including healthcare shortages and disruptions.

The authors recommended a future study of maternal mortality to examine how the pandemic has worsened racial and ethnic disparities in mortality. Additionally, work should be conducted to more accurately identify the causes of maternal deaths during the COVID-19 pandemic.