COVID-vaccination prior to or during pregnancy is not associated with an increased risk of preterm labor

08-09-2023

Moeders van Morgen Lareb (the Dutch Pregnancy Drug Register) demonstrated that COVID-19 vaccination prior to or during pregnancy is not associated with an increased risk of preterm labor. This was seen in each trimester.

In this prospective cohort study, we included 5,910 pregnant women who entered the Dutch Pregnancy Drug Register between February 2021 and August 2022. Information on COVID-19 vaccinations, preterm labor and confounders were self-reported using web-based questionnaires.

Researchers of the Moeders van Morgen Lareb team determined if and how often preterm labor occurred after COVID-19 vaccination.

No increased risk of preterm labor
In total, 5,227 (88%) received at least one COVID-19 vaccination between gestational week 2 and 37. Most women were vaccinated with an mRNA vaccine from Pfizer-BioNTech (BNT162b2, 85%) or Moderna (mRNA-1273, 12%). A small percentage of women reported to be vaccinated with a vector vaccine from Oxford-AstraZeneca (ChAdOx1 nCoV-19, 1%) or Janssen (Ad26.COV2.S, <1%). The risk of preterm labor was not different for women who were vaccinated prior to or during pregnancy compared to women who were not vaccinated.

Trimester
The risk of preterm labor after COVID-19 vaccination was also estimated for each trimester of pregnancy. Researchers observed no association between the risk of preterm labor and COVID-19 vaccination in any trimester of pregnancy.

Safe for mother and child
Other international studies have shown there are no increased risks of adverse pregnancy outcomes after COVID-19 vaccination. These results add to the growing evidence supporting safety of COVID-19 vaccination during pregnancy.