Comparison of Perceived Adverse Events After COVID-19 Vaccination Between Pregnant and NonPregnant Women Using Two Cohort Studies in the Netherlands

Abstract

Background: Maternal vaccines are upcoming. A clear picture of the adverse events (AEs) after maternal vaccination and whether this is comparable to a nonpregnant population is important. The objective of our study was to compare perceived AEs after COVID-19 vaccination between pregnant and nonpregnant women and to study if it is feasible to compare AEs within two independent Dutch cohort studies.

Methods: Data from the Dutch Pregnancy Drug Register (DPDR) and the cohort event monitoring (CEM) study on COVID-19 vaccines were used. At least one self-reported (solicited) AE, more than one AE, and specific self-reported AEs after the first doses of an mRNA COVID-19 vaccine were compared between pregnant and nonpregnant women using multivariable logistic regression analysis.

Results: The pattern of AEs was similar between pregnant (n = 2204) and nonpregnant (n = 2684) women, with the four most frequently reported AEs being: injection site reaction, myalgia, fatigue, and headache. Pregnant women reported less often at least one AE compared to nonpregnant women (65.9% vs. 72.3%; adjusted odds ratio [aOR] = 0.78; 95% confidence interval [CI] = 0.67-0.90), more than one AE, or specific AEs: nausea, chills, pyrexia, and arthralgia. Myalgia was more often reported among pregnant women compared to nonpregnant women.

Conclusions: Pregnant women perceived comparable or less often AEs after the first mRNA COVID-19 vaccination compared to nonpregnant women. The results aid pregnant women in making an informed decision about vaccination. A comparison between the pregnancy registry and the CEM study was feasible and this method can be used to compare AEs for other/future maternal vaccines.

Keywords: COVID‐19 vaccine; SARS‐CoV‐2; adverse events; cohort event monitoring; pregnancy.

FIGURE 1

Flowchart of the study population selection for the Dutch Pregnancy Drug Register (DPDR) and the cohort event monitoring (CEM) study on COVID‐19 vaccines separately. AEs, Adverse events. † Less than 2 weeks apart.

FIGURE 2

Prevalence of perceived adverse events (AEs) by pregnancy status. AEs, Adverse events; CEM, Cohort event monitoring study on COVID‐19 vaccines; DPDR, Dutch Pregnancy Drug Register.

FIGURE 3

Prevalence of perceived adverse events (AEs) by pregnancy status and study cohort. AEs, Adverse events; CEM, Cohort event monitoring (CEM) study on COVID‐19 vaccines; DPDR, Dutch Pregnancy Drug Register.* Chi‐square p‐value < 0.05.