Objectives <p>This study investigated whether county COVID-19 infection rates during the first trimester were associated with adverse pregnancy outcomes and whether those disproportionately impacted Black or Hispanic women.</p> Methods <p>This study used birth outcomes data 2018 through 2022 for four of Florida’s five largest counties. Outcomes were paired with census tract socioeconomic characteristics and with COVID-19 infection rates during the first trimester in the woman’s home county. Outcome measures included preterm birth, low birthweight and very low birthweight. Multivariate regression was used to test the association between infection rates and all outcomes. Then, a difference-in-difference approach was used to assess the impact of infection rates on racial and ethnic outcome disparities.</p> Results <p>County infection rates during the first trimester were significantly associated with worse pregnancy outcomes for all women. Each 1% point increase in COVID-19 cases during the first trimester was associated with a 5.16% point increase in the probability of preterm birth, a 4.35% point increase in the probability of low birth weight, and a 2.59% point increase in the probability of very low birth weight. Compared to White women, each 1% point increase in cases of COVID-19 during the first trimester caused a 1.21% point increase in the probability of preterm births, a 1.57% point increase in the probability of low birthweight, and a 1.28% point increase in the probability of very low birthweight among Black women. While no significant differences were observed in the probabilities of preterm birth and low birthweight between White and Hispanic women, the result revealed that each 1% point increase in cases of COVID-19 during the first trimester caused a 0.23% point increase in the probability of very low birthweight among Hispanic women compared to White women.</p> Conclusions for Practice <p>This study found evidence that local COVID-19 infection rates during the first trimester are associated with worse pregnancy outcomes. Moreover, the findings indicate that local COVID-19 infection rates during the first trimester exacerbate racial disparities in these outcomes.</p>