Safety-Related Outcomes of Novel mRNA COVID-19 Vaccines in Pregnancy

The objective of this study was to describe the safety profile and demographic data for a cohort of pregnant individuals who received an mRNA coronavirus disease 2019 (COVID-19) vaccine.

Prospective cohort study (with exposure matching) of individuals with active pregnancy who underwent immunization with a novel mRNA COVID-19 vaccine matched 1:2 with vaccinated age-matched female nonregnant controls was carried out. The primary outcome was defined as any vaccine-related complaints as defined in the original safety data. Secondary outcomes included specific complaints, COVID-19 screening test, and positive COVID-19 test.

Eighty-three vaccinated pregnant persons were age-matched with 166 female controls, all of whom were vaccinated between December 2020 and January, 2021. There was no difference in race or ethnicity between the groups. The mean body mass index of pregnant patients was lower than that of controls (26.1 vs. 29.2, p = 0.002). The frequency of complaints following vaccine administration was not different between pregnant and nonpregnant patients (18.1 vs. 16.9%, p = 0.201). Pregnant individuals were more likely to report fever (4.8 vs. 0.6%, p = 0.044) and gastrointestinal symptoms (4.8 vs. 0%, p = 0.012).

Side effect profiles of COVID-19 vaccine administration at our institution were relatively similar between pregnant and nonpregnant individuals and no serious complications occurred in either group. As COVID-19 infection in pregnancy can have significant morbidity, our data support the continued use of the vaccine for pregnant patients.

· Pregnant and nonpregnant women had a similar frequency of complaints.. · No serious adverse outcomes were observed in either group.. · Pregnant women were more likely to report fever and gastrointestinal side effects which may reflect gestationally mediated physiological responses to immunization..