Studies find COVID-19 vaccine does not increase risk of miscarriage

Only 1/3 of pregnant women are fully vaccinated
Posted at 6:08 AM, Nov 29, 2021
and last updated 2021-11-29 10:22:05-05

SAN DIEGO (KGTV) - A pair of recent studies show that the COVID-19 vaccine does not increase the risk of miscarriage among pregnant women. Now, doctors say they're working diligently to convince expecting mothers to get their shots.

"There are all sorts of things women are warned to be worried about," says Dr. Elyse Kharbanda with HealthPartners Institute for Medical Research. "You're told to worry about what you eat, what you drink. So I think it's natural to worry about a new vaccine."

According to the CDC, only 35.3% of pregnant women are fully vaccinated. To alleviate some of the worries, Dr. Kharbanda and her colleagues recently studied the odds of miscarriage after a COVID-19 vaccination.

Their research used data from the Vaccine Safety Datalink, a network of nine health systems across the US.

From December 2020 through June of 2021, they identified 105,446 pregnancies. Of those, 14.3 had been fully vaccinated before their 20th week of gestation.

By studying the outcomes of those pregnancies, the data showed no difference in the rates of miscarriage among women who had been vaccinated compared to women who hadn't.

"The adjusted odds ratio was 1.02," says Dr. Kharbanda. "1.0 means there was no difference. 1.02 is basically no difference between the groups."

The study found similar results no matter the woman's age or which form of vaccine she used.

"It's incredibly important," says Dr. Cynthia Gyamfi-Bannerman, the Chair of Obstetrics at UC San Diego Health.

She says getting concrete data to support vaccine recommendations helps convince women to get their shot.

"We knew the right thing to do from a biological standpoint," she says. "But now we have so much more assurance that it's the right thing to do."

Another study from the New England Journal of Medicine came to a similar conclusion. Researchers in that study tracked rates of miscarriages among women who had been vaccinated and compared them to historical rates of miscarriages.

That study found 14.1% of women who got an M-RNA vaccine reported miscarriages. That's within the historical range, which varies from 10-20%.

"It was a different health system, different population, but they did come to similar results as ours, that there was no association between the vaccination and miscarriage," says Dr. Kharbanda.

"I think it's really important to look at these issues with outcomes using different methods and different approaches. And if we all get to the same answer, then it's more reassuring."

"I think those go a long way to convince a patient who might be hesitant that they should get vaccinated during pregnancy," says Dr. Gyamfi-Bannerman.

Other research shows COVID-19 infections can be more severe in pregnant women, with higher rates of hospitalization and death.

That's why UC San Diego Health just released new information promoting the vaccine's benefits and urging expecting mothers to get their shot.

"The most important message here is that if you're pregnant, and you're at all considering vaccination, you should get vaccinated," says Dr. Gyamfi-Bannerman. "And if you're not considering it, you should be considering it."

Doctors say more research is needed into other possible impacts of COVID-19 and the vaccine on pregnant women. They're looking into how it can impact pre-term births, birth weight, and if vaccine immunity can pass from mother to child.

They say they'll be looking for answers for years.