Severe maternal morbidity by race and ethnicity before vs. during the COVID-19 pandemic

PURPOSE: To examine the change in racial disparity in severe maternal morbidity (SMM) during the COVID-19 pandemic and the associations between SARS-CoV-2 infection and SMM. METHODS: This retrospective cohort study used linked databases of all livebirths delivered between 2018 and 2021 in South Carolina (n = 162,576). Exposures were 1) pre-pandemic and pandemic periods (before vs. March 2020 onwards); 2) SARS-CoV-2 infection, severity, and timing of first infection. Log-binomial regression models were used. RESULTS: SMM rate was higher among pandemic childbirths than pre-pandemic period (p = 0.06). The risk of SMM among Hispanics was doubled from pre-pandemic to pandemic periods (adjusted relative risk (aRR)= 2.50, 95% CI: 1.27, 4.94). During pre-pandemic, compared to White women, Black women (aRR=1.37, 95% CI: 1.14-1.64), while Hispanics had lower risk of SMM (aRR=0.42, 95% CI: 0.24-0.73). During the pandemic, the Black-White difference in the risk of SMM persisted (aRR=1.24, 95% CI: 1.00-1.54) and Hispanic-White difference in SMM risk became insignificant (aRR=0.85, 95% CI: 0.54-1.34). SARS-CoV-2 infection, its severity, and the late diagnosis were associated with 1.78-5.06 times higher risk of SMM. CONCLUSIONS: During pandemic, Black-White racial disparity in SMM persisted but the relative pre-pandemic advantage in SMM among Hispanic women over White women disappeared during the pandemic.