Pregnancy and birth outcomes after SARS-CoV-2 vaccination in pregnancy

Background

SARS-CoV-2 infection during pregnancy is associated with significant maternal morbidity and increased rates of preterm birth. For this reason, COVID-19 vaccine administration in pregnancy has been endorsed by multiple professional societies including ACOG and SMFM despite exclusion of pregnant women from initial clinical trials of vaccine safety and efficacy. However, to date little data exists regarding outcomes after COVID-19 vaccination of pregnant patients.

Study Design

A comprehensive vaccine registry was combined with a delivery database for an integrated healthcare system to create a delivery cohort including vaccinated patients. Maternal sociodemographic data were examined univariately for factors associated with COVID-19 vaccination. Pregnancy and birth outcomes were analyzed, including a composite measure of maternal and neonatal pregnancy complications, the Adverse Outcome Index.

Results

Of 2002 patients in the delivery cohort, 140 (7.0%) received a COVID-19 vaccination during pregnancy and 212 (10.6%) experienced a COVID-19 infection during pregnancy. The median gestational age at first vaccination was 32 weeks (range 13 6/7-40 4/7), and patients vaccinated during pregnancy were less likely than unvaccinated patients to experience COVID-19 infection prior to delivery (1.4% (2/140) vs. 11.3% (210/1862)) P<0.001No maternal COVID-19 infections occurred after vaccination during pregnancy.

Factors significantly associated with increased likelihood of vaccination included older age, higher level of maternal education, lower pre-pregnancy BMI, and use of infertility treatment for the current pregnancy. Tobacco or other substance use, Hispanic ethnicity, and higher gravidity were associated with a lower likelihood of vaccination. No significant difference in the composite adverse outcome (5.0% (7/140) vs. 4.9% (91/1862) P=0.95) or other maternal or neonatal complications, including thromboembolic events and preterm birth, was observed in vaccinated mothers compared to unvaccinated patients.

Conclusions

Vaccinated pregnant women in this birth cohort were less likely to experience COVID-19 infection compared to unvaccinated pregnant patients, and COVID-19 vaccination during pregnancy was not associated with increased pregnancy or delivery complications. Significant sociodemographic disparities in vaccine uptake and/or access were observed among pregnant patients, and future efforts should focus on outreach to low-uptake populations.