Impact of COVID-19 on Pregnancy Outcomes across Trimesters in the United States

Background: Evidence on trimester-specific risks of COVID-19 in pregnancy remains limited. Using the US National Inpatient Sample (NIS) 2020, we examined trimester-specific outcomes among hospitalized pregnant women with COVID-19. Results: Among 3,447,771 pregnant women identified, those with COVID-19 had higher in-hospital mortality in the third trimester than those without COVID-19. Mechanical ventilation, acute kidney injury (AKI), renal replacement therapy, and perinatal complications (preeclampsia, HELLP syndrome, preterm birth) were significantly elevated across trimesters in COVID-19 patients. COVID-19 was more prevalent among low-income, Hispanic pregnant women. Conclusions: COVID-19 during pregnancy is associated with increased maternal mortality and complications, particularly in the third trimester, and substantial racial/socioeconomic disparities. Equitable healthcare strategies are needed to mitigate adverse maternal and fetal outcomes.