[Self-reported maternal adverse events of covid-19 vaccination during pregnancy]

To describe the self-reported maternal adverse events (AEs) of covid-19 vaccination during pregnancy.

The Dutch Pregnancy Drug Register ("Moeders van Morgen"), is a prospective cohort study among pregnant women in the Netherlands.

Using online questionnaires, women reported whether they received a covid-19 vaccination and the self-perceived AEs after vaccination. We included women who received their first covid-19 vaccination during pregnancy. We assessed the maternal AEs by vaccine dose, type of vaccine (BioNTech/Pfizer, Moderna, AstraZeneca, and Janssen) and moment of vaccination in pregnancy.

4348 women received their first covid-19 vaccination during pregnancy and were included. Of these, 2787 women also reported a second dose during pregnancy. After the first dose, AEs were less often reported for BioNTech/Pfizer (56% ≥1 AE), compared to Moderna (68% ≥1 AE) or AstraZeneca (87% ≥1 AE). After the second dose, AEs were less often reported for BioNTech/Pfizer (44% ≥1 AE) compared to Moderna (76% ≥1 AE). Injection site reactions, myalgia and fatigue were reported most frequently. There was large variation in the percentage reporting pyrexia/fever between the different vaccines (3%, 22%, and 10% after the second dose of BioNTech/Pfizer, Moderna, and Astrazeneca respectively). There were no major differences in the rates of AEs between vaccination in the first, second, or third trimester.

The adverse event profile among women who were vaccinated against covid-19 during pregnancy do not indicate any safety concerns. Considering the reported maternal AEs, the BioNTech/Pfizer vaccine seems best for vaccination during pregnancy.