Two studies published yesterday in JAMA, one from Sweden and Norway and one from Ontario, find no link between COVID-19 vaccination during pregnancy and adverse outcomes.No link to preterm birth, stillbirth, NICU admissionIn the first study, a team led by researchers from the Norwegian Institute of Public Health in Oslo and the Karolinska Institute in Stockholm studied 157,521 singleton pregnancies ending after 22 weeks' gestation among vaccinated and unvaccinated pregnant women listed in national birth registries.
The study period began Jan 1, 2021, ending on Jan 12, 2022, in Sweden, and 3 days later in Norway.Of the 157,521 births, 103,409 took place in Sweden, and 54,112 occurred in Norway.
Average maternal age was 31 years, and 18% were vaccinated against COVID-19 during pregnancy (12.9% with Pfizer/BioNTech, 4.8% with Moderna, and 0.3% with AstraZeneca/Oxford).
Among the vaccinated women, 4.4% received only one vaccine dose, while 13.7% had two.A total of 0.7% of women were vaccinated during the first semester, while 8.3% and 9.1% were vaccinated during the second and third trimesters, respectively.