COVID-19 Vaccine and Pregnancy: What You Need to Know

An expert discusses encouraging new research about pregnant women who have received the vaccine.

Pregnant woman considering COVID-19 vaccine

With COVID-19 vaccinations well underway in the U.S., an important question is being asked: Is the COVID-19 vaccine safe for pregnant women? The three vaccines authorized by the U.S. Food and Drug Administration (FDA) for emergency use did not include women who were pregnant or breastfeeding in their initial clinical trials. This absence of data left many pregnant people unsure as to whether they should get the vaccine.

Now, new studies involving pregnant women who received the COVID-19 vaccine are offering encouraging data to help women make a decision. A study recently published in the New England Journal of Medicine “did not identify any safety concerns for pregnant people who were vaccinated or for their babies,” says the Centers for Disease Control and Prevention (CDC).

The study evaluated data from more than 35,000 pregnant participants who received the Pfizer or Moderna vaccine, which are mRNA vaccines. The pregnant women reported typical reactions after receiving the vaccine, though they were slightly more likely to report injection site pain than women who weren’t pregnant and less likely to report some other reactions such as headaches, muscle aches, chills, and fever. The study also didn’t identify safety concerns for the babies born to vaccinated women during the study period. The rates of miscarriage, preterm births, low-birth weight, and birth defects were similar to pregnancy outcomes before the pandemic, researchers wrote.

Dr. Laura Riley

Dr. Laura Riley

“The data from the study should be very reassuring to pregnant women,” says Dr. Laura Riley, obstetrician and gynecologist-in-chief at NewYork-Presbyterian/Weill Cornell Medical Center.

In addition, a new study published in Obstetrics & Gynecology found that women in their third trimester of pregnancy who received the Pfizer or Moderna vaccine passed protective antibodies through the umbilical cord to their babies. Ninety-nine percent of newborns had protective antibodies after their mothers received two doses of the COVID-19 vaccine, the study by NewYork-Presbyterian and Weill Cornell Medicine researchers found.

“It shows that there may be an added benefit to the vaccine, because now the vaccine protects not only you, it may also protect your baby,” says Dr. Riley, one of the study’s authors.

Dr. Riley says the growing data on the safety of the vaccine for pregnant women is exciting.

“Based on how the vaccines work, we don’t think there’s any biologic reason that we should be concerned about their safety in pregnancy,” says Dr. Riley, who is also the chair of the Department of Obstetrics and Gynecology at Weill Cornell Medicine and a member of the COVID-19 expert work group at the American College of Obstetricians and Gynecologists (ACOG). “What’s really important is that we do have lots of epidemiologic data which suggests that pregnancy plus COVID-19 is not a good mix. Pregnant women have had more admissions to the ICU, more mechanical ventilation, and more deaths, although the absolute number is low. The flip side is you’ve got a vaccine that works to prevent severe illness.”

Dr. Riley shared with Health Matters what women who are pregnant, thinking about getting pregnant, or lactating should know about the COVID-19 vaccines.

What is the recommendation for pregnant women?

The CDC and ACOG say if you are pregnant, you should have access to the vaccine. You should be offered it just like anybody else. You do not need a doctor’s approval. You can make that decision. But if you want to talk more with someone about the pros and cons, then I would suggest you talk to your OB or your midwife.

What about women who are breastfeeding?

They should get the vaccine and protect themselves from getting COVID. The way this vaccine works, there’s no reason to suspect that it gets into breast milk and can in any way get to the child. We give vaccines to lactating women all the time. And we definitely don’t want people to stop breastfeeding to get the vaccine.

Should women who are planning to get pregnant have any reservations?

No. They should just go ahead and get it done. If by chance you become pregnant between the first and second dose, you should complete the series and attain the maximal benefit from the vaccine. The last thing they need is to be in the first trimester and get COVID-19. We know that the vaccine is the best possible intervention to protect ourselves from COVID-19.

Can the COVID vaccine cause infertility?

There is no evidence that the COVID vaccine can cause infertility. In clinical trials and among the millions of people who have received the vaccine, we’ve seen no link between the vaccine and a loss of fertility. The American Society for Reproductive Medicine recommends the vaccine for those seeking to become pregnant.

“There is no evidence that the COVID vaccine can cause infertility.”

— Dr. Laura Riley

When should pregnant women get the vaccine?

As soon as it’s available to them. If you haven’t been vaccinated prior to pregnancy and then you get pregnant, and you can now get the vaccine, get it. It’s to protect the mother. There’s no data that suggests that the first, second, or third trimester is better.

Are the vaccine makers planning trials in pregnant women?

Yes. There are two pieces of information that are very reassuring. One, given our understanding of the way the vaccine works within the body, we do not have concerns that it will be problematic for expectant mothers or their babies. Two, there is reproductive animal data on all three vaccines. These studies found no safety concerns in pregnant animals or their babies. That animal data was reviewed by the FDA before emergency use authorization was granted and before human pregnancy trials could start. Pfizer recently began pregnancy trials, and Moderna has a registry to monitor pregnant women.

How will safety continued to be studied?

Everyone’s concerned about safety. There’s already a really robust safety system for vaccines in the U.S. There are many different safety systems that either patients or their providers can feed information into after a vaccine and say, “I had this complication,” if there was one. And something I’m really excited about is that they’ve added yet another system, which is called V-safe. Once you’re vaccinated, you can just log on and register yourself with the vaccine that you got, and then it asks you daily questions about how you’re feeling. Not only is that yet another safety system, but they have built-in pregnancy questions, which, having done this for years, the other systems don’t really pick up pregnancy well. The New England Journal of Medicine study on pregnant people who received the vaccine evaluated data from pregnant people who participated in V-safe. The other thing to know is that there’s a group at the CDC that is tasked with looking at the data from all these safety systems every single week, and reporting on anything we see that is of concern. And that’s important because we don’t know everything about these vaccines. Everything we know thus far it looks safe, but as we roll it out to millions, we need to remain vigilant and investigate any potential concerns. If a concern is raised, it will be investigated and reported in a timely manner.

Additional Resources

Laura Riley, M.D., is obstetrician and gynecologist-in-chief at NewYork-Presbyterian/Weill Cornell Medical Center and chair of the Department of Obstetrics and Gynecology at Weill Cornell Medicine. Dr. Riley is chair of the American College of Obstetricians and Gynecologists’ Immunization and Emerging Infections Expert Work Group and has served as a member of the Advisory Committee on Immunization Practice at the Centers for Disease Control and Prevention. She is the author of two books, You and Your Baby: Pregnancy and You and Your Baby: Healthy Eating During Pregnancy.

Note: Following CDC, FDA and New York State guidance, NewYork-Presbyterian has resumed the use of the Johnson & Johnson COVID-19 vaccine, in addition to continuing to offer the Pfizer and Moderna vaccines

If you received the J&J vaccine within the last three weeks and develop severe headache, abdominal pain, leg pain, or shortness of breath, please contact your health care provider.