(873) The Relationship between COVID-19 Vaccination Status in Pregnancy and Birth Weight

We performed a population-based cohort study using the Vizient® clinical database, which included data from 192 hospitals in 38 states. Our sample includes pregnant persons who delivered between January 2021 and April 2022 at hospitals that reported patient vaccination data and known birth weight at delivery. Pregnant persons were categorized into three groups: unvaccinated; incompletely vaccinated (one dose of Pfizer or Moderna); or completely vaccinated (one dose of Johnson & Johnson or ≥ two doses of Moderna or Pfizer). Demographics and outcomes were analyzed using standard statistical tests. Multivariable logistic regression models were used to adjust for potential confounders between vaccination status and LBW with adjusted odds ratio (aOR) as the measure of treatment effect.

Results: Of 390,337 participants, 36,236 had LBW, and these patients were also more likely to be unvaccinated (Table 1). Partially vaccinated pregnant persons were 16% less likely to have LBW neonates compared to unvaccinated persons (OR 0.84, 95% CI 0.71-0.99, p=0.05), and completely vaccinated persons were 23% less likely to have LBW neonates (OR 0.77, 95% CI 0.69-0.87, p < 0.001). When controlling for age, race, hypertension, diabetes, lupus, tobacco use, multifetal gestation, obesity, and assisted reproductive technology, these associations remained significant for incompletely vaccinated (aOR 0.82, 95% CI 0.69-0.98, p=0.03) and completely vaccinated (aOR 0.78, 95% CI 0.69-0.88, p < 0.001) persons (Table 2).

Conclusion: Compared to unvaccinated and incompletely vaccinated persons, completely vaccinated pregnant persons were least likely to have LBW neonates. These associations will require further prospective validation.