Aim: To compare prevalence and disease severity of Severe Acute Respiratory Syndrome Coronavirus 2 (COVID-19) among multiparous and nulliparous pregnant patients at a rural Midwest tertiary care hospital; parity used as a surrogate for having additional children, assessing if exposure to other coronaviruses is protective for COVID-19.

Methods: Retrospective cohort study included all patients who delivered at the University of Iowa between May 1, 2020 and September 22, 2020. Reverse transcriptase polymerase chain reaction and plasma antibody testing for COVID-19 were performed on women at the time of delivery. Demographics and outcome information were obtained from the electronic medical record. Adjusted odds ratio estimates for COVID-19 risk factors were obtained through the generalized linear modeling framework.

Results: In 1,001 delivering patients, 6.2% tested positive for COVID-19 by either viral or antibody tests. Comparing infection rates by parity strata revealed no significant distinctions, with 5.4% of nulliparous women and 6.7% of multiparous women positive by either test (p=0.41). Odds of COVID-19 infection decreased by 6.2% for each year of maternal age (p=0.02).

Conclusion: No significant associations were found between parity and prevalence or severity of COVID-19 infection in this population. Increasing maternal age and decreased COVID-19 frequency demonstrated a significant association.