AN ANALYSIS OF PERINATAL COVID-19 INFECTION AND PRETERM BIRTHS IN A MICHIGAN-BASED COHORT

Background: COVID-19 infection during pregnancy has been previously associated with an increased risk of preterm birth. This retrospective, population-level observational study uses data from the Michigan Department of Health and Human Service’s COVID-19 Pregnancy and Neonate Surveillance project, along with birth certificate and abstracted medical record data, to assess the risk of preterm birth amongst a 2020 cohort of Michigan residents who tested positive for SARS-CoV-2 during pregnancy.Methods: Logistic regression analysis produced odds ratios, 95% confidence intervals, chi-square values, and p-values. Several covariates were evaluated as potential confounders, though none met the threshold to require adjustment. To examine possible effect modification, the model was stratified by pre-pregnancy BMI, race, and trimester of infection.Results: The odds of preterm birth was 27% higher amongst the COVID-positive pregnancies in this cohort compared to COVID-negative pregnancies (95% CI: 0.99-1.63; p=0.062), but these results were not statistically significant at p<0.05. Exploratory findings did identify higher odds of preterm birth amongst pregnancies that tested positive for COVID-19 between 14-26 weeks (OR: 2.10; 95% CI: 1.30-3.39; p=0.002), as well as those who were a race other than non-Hispanic Asian or white (OR: 1.49; 95% CI: 1.08-2.07; p= 0.016). Conclusions: While this study could not conclude that there was an association between prenatal COVID-19 infection and preterm birth in this cohort, stratification did find increased risk amongst non-white/Asian pregnancies and second trimester infections. As COVID-19 continues into endemicity, vaccination and other preventative measures should be prioritized prior to conception and during pregnancy.