There's No Evidence That the COVID-19 Vaccines Increase Miscarriage Risk

If you’re on social media, you’ve likely encountered misinformation about the COVID-19 vaccine. Unfortunately, many of these rumors focus on miscarriage, with some viral posts claiming that the vaccine increases risk of pregnancy loss.

Miscarriage, the unexpected end of a pregnancy before 20 weeks, occurs in around 10 to 20 percent of known pregnancies, and pregnancy loss is understandably one of the biggest things parents-to-be worry about. But if you've been holding off on getting a COVID-19 vaccine or booster due to concerns that the shot might increase your risk of miscarriage, you should feel reassured that the vaccines have been found to be safe and effective for pregnant women.

In fact, leading health officials and experts from groups such as the Centers for Disease Control and Prevention (CDC), the American College of Obstetricians and Gynecologists (ACOG) and the Society for Maternal Fetal Medicine (SMFM) strongly recommend that all pregnant people get the COVID-19 vaccine.

"[W]e all know that pregnancy, there is always a risk of a spontaneous miscarriage," said Dr. Anthony Fauci, Director of the National Institute of Allergy and Infectious Diseases and Chief Medical Advisor to the President, in an interview with What to Expect founder Heidi Murkoff. "However, when you look at the unvaccinated versus the vaccinated, there is absolutely no increased risk of that."

Here’s what the research shows, and why you can feel confident getting the COVID-19 vaccine at any point during your pregnancy.

Do the COVID-19 vaccines increase risk of miscarriage?

“We now have enough data to show that the COVID-19 vaccines don’t increase miscarriage risk,” says Audrey Merriam, M.D., a high-risk pregnancy specialist at Yale Medicine in New Haven, Connecticut. “But many women are still afraid to get the vaccine, or want to wait until the end of their first trimester, when there’s no reason they need to do so.”

An October 2021 study released by the CDC in the New England Journal of Medicine analyzed safety data on 2,500 women who received at least one dose of the Pfizer-BioNTech or Moderna vaccine either right before getting pregnant or in the first half of their pregnancy, and found no increased risk of miscarriage. Miscarriage rates in the study were around 13 percent, which is within the normal range of most pregnancies, notes Dr. Merriam.

Another study published in the Journal of the American Medical Association looked at CDC data for 105,000 pregnancies from nine different health systems through June, and also did not find higher miscarriage rates among recently vaccinated women.

Leading experts stress that it's much riskier for a pregnant person to get the COVID-19 virus. Not only are pregnant people more vulnerable to complications from COVID-19, including hospitalization, intubation and preterm birth, but a review of 11 studies published in August 2021 in the medical journal PLOS One found increased risk of miscarriage among pregnant moms who contracted COVID-19.

“We know that if you run a high fever in the first trimester of pregnancy, you have a greater risk of miscarriage,” Dr. Merriam explains. “That’s very different from the low-grade fever you might get from a COVID-19 vaccine.”

How do we know the COVID-19 vaccines are safe? 

On August 23, 2021, the FDA gave full approval to the Pfizer-BioNTech vaccine for the prevention of COVID-19 in those 16 and older. That was followed in January 2022 by full approval for the Moderna vaccine. The Johnson & Johnson vaccine is still operating under an emergency use authorization. (Public health officials have increasingly recommended that people get the Pfizer-BioNTech or Moderna vaccines over Johnson & Johnson, if they’re able.)

Although it may seem like the vaccines were developed quickly, “we’ve actually been studying [these types] for decades, so we have strong safety data,” notes William Schaffner, M.D., an infectious disease specialist at Vanderbilt University Medical Center in Nashville, Tennessee.

In the U.S., all vaccines undergo clinical trials to test their safety and effectiveness, and the COVID-19 vaccines were no exception. They were given to tens of thousands of people in areas where high levels of COVID-19 were circulating, which allowed researchers to get data fairly quickly, notes Dr. Schaffner.

The drug companies also ramped up production at the same time as clinical trials were ongoing to ensure there would be a ready supply once vaccines were authorized for emergency use by the Food and Drug Administration (FDA).

The FDA and the CDC continue to monitor thesafety of the vaccines. The CDC itself has three safety registries to examine the effects of the vaccine on pregnant women: the Vaccine Adverse Events Reporting System (VAERS), the V-Safe COVID-19 Vaccine Pregnancy Registry and the Vaccine Safety Datalink (VSD).

After the vaccines received emergency use authorization, both the FDA and the CDC continued to monitor their safety. The CDC itself has three safety registries to examine the effects of the vaccine on pregnant women: the Vaccine Adverse Events Reporting System (VAERS), the V-Safe COVID-19 Vaccine Pregnancy Registry and the Vaccine Safety Datalink (VSD). 

What's more, emerging research suggests that getting the vaccine during pregnancy can benefit your baby. Some studies have found the antibodies made after pregnant and breastfeeding women received an mRNA COVID-19 vaccine were also found in their breast milk and in baby’s umbilical cord blood. And a large Norweigan study published in June 2022 found that newborns were less likely to test positive for COVID-19 in the first four months of life if their mothers were vaccinated while pregnant.

“I love evidence-based medicine, and when it comes to the use of the COVID-19 vaccine during pregnancy, we now have plenty of it,” says Oluwatosin Goje, M.D., professor of obstetrics and gynecology at the Cleveland Clinic and member of the What to Expect Medical Review Board. “I tell my patients they can feel very confident that getting the vaccine won’t raise their risk of miscarriage in any way.”