Two studies in major medical journals add to evidence that COVID-19 vaccines are safe before and during pregnancy.

One study, published in The New England Journal of Medicine, tracked nearly 18,500 pregnant women in Norway, including about 4,500 who had miscarriages. Researchers found no link between COVID-19 vaccines and risk of first-trimester miscarriage, regardless of whether the vaccines were from Moderna, Pfizer and BioNTech, or AstraZeneca.

Overall, the women with miscarriages were 9 percent less likely to have been vaccinated, according to the researchers’ calculations.

In a separate study published in The Lancet, researchers tracked 107 women who became pregnant while participating in trials of AstraZeneca’s vaccine in the UK, Brazil and South Africa. Seventy-two of the women had received the vaccine while the others got a placebo. AstraZeneca’s vaccine had no effect on the odds of safely carrying the pregnancy to term, the researchers reported.

“It is important that pregnant women are vaccinated since they have a higher risk of hospitalizations and COVID-19-complications, and their infants are at higher risk of being born too early,” the authors of the Norwegian study wrote.

“Also, vaccination during pregnancy is likely to provide protection to the newborn infant against COVID-19 infection in the first months after birth.”