On Jan. 28, 2021, National Institutes of Health (NIH) researchers reported that pregnant women who experienced severe symptoms of COVID-19 had a higher risk of complications during and after pregnancy, according to preliminary findings from the study. Compared to COVID-19 patients without symptoms, those with severe symptoms were at higher risk for cesarean delivery, postpartum hemorrhage, hypertensive disorders of pregnancy and preterm birth.

Researchers evaluated more than 1,200 pregnant women with COVID-19 who delivered at 33 U.S. hospitals between March 1 and July 30, 2020. Roughly half of the women (47%) were asymptomatic, 27% had mild symptoms, 14% had moderate symptoms, 8% had severe symptoms and 4% were critically ill. Those with more severe symptoms tended to be older, with a higher than average body mass index and underlying health issues, such as asthma, diabetes, hypertension, liver disease and seizure disorder.

Researchers attributed four maternal deaths to COVID-19. Transmission of SARS-CoV-2, the virus that causes COVID-19, from mother to child was rare, with 1% of newborns testing positive for the virus before discharge from the hospital.