The risk of miscarriage after COVID‐19 vaccination before and during pregnancy

• Published in: Pharmacoepidemiology and drug safety 2024-01, Vol.33 (1), p.e5724-n/a
• Main Authors: Feijter, Maud, Gelder, Marleen M. H. J., Vissers, Lieke C. M., Kant, Agnes C., Woestenberg, Petra J.
• Format: Article
• Language: English
• Subjects: Abortion, Spontaneous - chemically induced; Abortion, Spontaneous - epidemiology; Adult; Cohort Studies; COVID-19; COVID-19 - epidemiology; COVID-19 - prevention & control; COVID-19 vaccines; COVID-19 Vaccines - adverse effects; Female; Humans; Immunization; Miscarriage; Pregnancy; prospective cohort; SARS-CoV-2; Severe acute respiratory syndrome coronavirus 2; Vaccination - adverse effects; vaccination safety
• ISSN: 1053-8569; 1099-1557; 1099-1557
• DOI: 10.1002/pds.5724

Purpose Pregnant women are at higher risk of severe illness and adverse pregnancy outcomes due to a SARS‐CoV‐2 infection, which can be prevented by vaccination. Observational studies are needed to ascertain the safety of COVID‐19 vaccination during pregnancy. We aimed to determine whether COVID‐19 vaccination before and during pregnancy is associated with the risk of miscarriage. Methods In this cohort study, we included 4640 pregnant women (mean age: 32.8 ± 3.7 years) from the Dutch Pregnancy Drug Register between February 2021 and August 2022. Information on COVID‐19 vaccinations, miscarriage, and confounders was self‐reported, using web‐based questionnaires. The hazard ratio (HR) of miscarriage (in gestational weeks 6–20) after a COVID‐19 vaccination, was estimated using the survival analyses. A COVID‐19 vaccination during pregnancy (≥1 COVID‐19 vaccination between week 2 and 20 of pregnancy) was included as a time‐dependent exposure and vaccination prior to pregnancy was included as a binary exposure. Results A total of 3202 pregnant women (69%) received ≥1 COVID‐19 vaccine in gestational week 2–20. We observed no association of vaccination during pregnancy with the risk of miscarriage (adjusted HR = 1.29, 95% CI = 0.93–1.74). Vaccination prior to pregnancy, however, was associated with a decreased risk of miscarriage (adjusted HR = 0.69, 95% CI = 0.48–0.99). Conclusions We demonstrated that COVID‐19 vaccination during pregnancy is not associated with an increased risk of miscarriage in gestational weeks 6–20. This study adds to the growing body of evidence demonstrating the safety of COVID‐19 vaccination during pregnancy.