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• Posted November 7, 2023

COVID Vaccine Won't Raise Miscarriage Risk

A new study provides deeper insight into the safety of COVID-19 vaccines for people planning to become pregnant.

Boston University researchers found no increased risk of early or late-term miscarriage resulting from either the male or the female partner getting a COVID-19 vaccination prior to conceiving.

This study was believed to be the first to evaluate risk of early miscarriage following a vaccine prior to conception. It defined early miscarriage as one before eight weeks' gestation.

“These findings should be replicated in other populations, but are reassuring for couples who are planning pregnancy,” lead author Jennifer Yland, who was a doctoral student in epidemiology Boston University School of Public Health (BUSPH) at the time of the study, said in a school news release.

The study actually found a slightly lower risk of miscarriage in participants who were vaccinated before trying to conceive.

For the study, researchers analyzed survey data on COVID vaccination and miscarriage among participants in the BUSPH-based Pregnancy Study Online, or PRESTO, for short.

That research, funded by the National Institutes of Health, enrolls women who are trying to conceive, and follows them through six months after delivery.

This study included more than 1,800 women in the U.S. and Canada who were followed from December 2020 through November 2022.

They were observed from the time of a positive pregnancy test until miscarriage, induced abortion, ectopic pregnancy or 20 weeks' gestation.

Seventy-five percent of the women had received at least one dose of a COVID vaccine by the time they became pregnant.

Nearly a quarter of the pregnancies resulted in miscarriage. About 75% of those occurred in the first eight weeks.

Risk of miscarriage was 26.6% among unvaccinated women, 23.9% among women who had received one dose of the vaccine before conception and 24.5% among those who completed a full primary series before conception, the study found.

It was 22.1% among those who completed the vaccine series three months before conception and 20.1% among those who received only one shot of a two-dose vaccine before conceiving.

“The rate of miscarriage among vaccinated individuals was not only comparable with that of PRESTO participants who conceived before the pandemic, but our data indicated a slightly lower risk of miscarriage among vaccinated individuals compared to unvaccinated individuals,” Yland said.

U.S. government health officials recommend COVID vaccination for anyone planning to conceive. The benefits outweigh any risks, they have said.

Study findings were recently published in the journal Human Reproduction.

More information

The U.S. Centers for Disease Control and Prevention has more on pregnancy and COVID-19.

SOURCE: Boston University School of Public Health, news release, Oct. 28, 2023