According to two studies, monovalent COVID-19 booster vaccinations administered in early pregnancy (before 20 weeks gestation) did not raise the risk of miscarriage. The findings of these two studies contribute to our knowledge concerning the safety of COVID-19 booster vaccines among pregnant women.

In the first study published in the journal JAMA Network Open, the researchers from HealthPartners Institute in Minneapolis, US, analyzed data from more than 100,000 pregnancies between six and 19 weeks gestation. In their study, they found that pregnant women who got their booster jab within 28 to 48 days were not associated with miscarriage.

Another study, also led by the HealthPartners Institute and published in the Obstetrics and Gynaecology journal, showed that booster dose immunization with the mRNA vaccine during pregnancy was not associated with an increased risk for serious acute adverse events.

In that study, researchers examined data from almost 80,000 pregnancies that occurred between September 23, 2021, and June 30, 2022. The findings of this study showed that booster immunization in pregnancy did not enhance the risk of thrombocytopenia, myocarditis, venous thromboembolism, ischemic stroke, or any major side events in the period of 21 to 42 days after vaccination.

(Source: https://medicalxpress.com/news/2023-05-adverse-pregnancy-outcomes.html)