On Jan. 29, 2026, in a new study from Sweden, researchers found no statistically significant difference in rates of childbirth or miscarriage among vaccinated and unvaccinated women. During the pandemic, many women were afraid to be vaccinated because of widespread misinformation that COVID-19 shots would harm their chances of getting pregnant.

“Unsubstantiated rumors about side effects of COVID-19 vaccines still are circulating on social media,” said Toomas Timpka, MD, PhD, senior author of the paper, published last week in Communications Medicine, and a professor of social medicine and public health at Linköping University. Although the study was not a randomized trial, the research “shows it is very highly unlikely that COVID-19 vaccines have any meaningful negative effect on fertility or childbirth rates,” Timpka told CIDRAP News.

Researchers were able to analyze medicals records of nearly 60,000 women ages 18 to 45 in one Swedish county because the country’s national health system keeps detailed records of births, deaths, vaccinations, and other key data. About 75% of women in the study were vaccinated from 2021 to 2024. Among those who were vaccinated, 97% received an mRNA vaccine.

When comparing childbirth rates and recorded miscarriages between vaccinated and unvaccinated women, the researchers found adjusted hazard ratios of 1.03 for childbirth — meaning that vaccinated women were 3% more likely to give birth —  and 0.86 for miscarriages — suggesting that vaccinated women were 14% less likely to have a miscarriage. The team’s analysis suggests neither ratio is statistically significant, meaning that the findings could have been due to chance.

A study published in December in JAMA found that pregnant women who develop COVID-19 after being vaccinated are much less likely to be hospitalized, need intensive care, or deliver early compared with women who aren’t vaccinated.

Rumors about COVID-19 vaccines and fertility have been fueled in part by widespread declines in birth rates during the pandemic, according to background information in the new paper.

In high-income countries around the world, birth rates fell during the pandemic, when many communities were locked down and suffering high rates of unemployment and inflation. Although birth rates rebounded after pandemic-era restrictions ended, rates dropped again in 2022.