Background Pregnant individuals are at increased risk of coronavirus disease 2019 (COVID-19) hospitalization and death, and primary and booster COVID-19 vaccination is recommended for this population. Methods Among a cohort of pregnant individuals who received prenatal care at 3 healthcare systems in the United States, we estimated the cumulative incidence of hospitalization with symptomatic COVID-19 illness. We also identified factors associated with COVID-19 hospitalization using a multivariable Cox proportional hazards model with pregnancy weeks as the timescale and a time-varying adjustor that accounted for severe acute respiratory syndrome coronavirus 2 circulation; model covariates included site, age, race, ethnicity, insurance status, prepregnancy weight status, and selected underlying medical conditions. Data were collected primarily through medical record extraction. Results Among 19 456 pregnant individuals with an estimated due date during 1 March 2020–28 February 2021, 75 (0.4%) were hospitalized with symptomatic COVID-19. Factors associated with hospitalization for symptomatic COVID-19 were Hispanic ethnicity (adjusted hazard ratio [aHR], 2.7 [95% confidence interval {CI}, 1.3–5.5]), Native Hawaiian or Pacific Islander race (aHR, 12 [95% CI, 3.2–45.5]), age <25 years (aHR, 3.1 [95% CI, 1.3–7.6]), prepregnancy obesity (aHR, 2.1 [95% CI, 1.1–3.9]), diagnosis of a metabolic disorder (aHR, 2.2 [95% CI, 1.2–3.8]), lung disease excluding asthma (aHR, 49 [95% CI, 28–84]), and cardiovascular disease (aHR, 2.6 [95% CI, 1.5–4.7]). Conclusions Although hospitalization with symptomatic COVID-19 was uncommon, pregnant individuals should be aware of risk factors associated with severe illness when considering COVID-19 vaccination. [ABSTRACT FROM AUTHOR]