One of the lingering questions about the COVID-19 vaccines has been how safe they are for pregnant people.
Cleveland Clinic is a non-profit academic medical center. Advertising on our site helps support our mission. We do not endorse non-Cleveland Clinic products or services. Policy
Historically, public health agencies have been slow to endorse vaccines for pregnant and breastfeeding people because of the potential risk and rigorous safety precautions needed to evaluate the vaccine in these groups.
But two recent studies of the COVID-19 vaccine given to pregnant patients have yielded good news about the vaccine’s safety and underscored the vaccine’s effectiveness in protecting both the patient and their child. And with the new data, the Centers for Disease Control and Prevention (CDC) is now more strongly endorsing the vaccination of pregnant people.
To learn more about the study and what it means, we spoke with Ob/Gyn Oluwatosin Goje, MD.
According to the study (which has not yet completed peer review), there is no increased risk of miscarriage in pregnant patients who receive either the Pfizer or Moderna vaccines. This is especially good news given the recent surge in cases across the country fueled by the highly contagious delta variant of the COVID-19 virus.
“We knew the vaccines were effective,” says Dr. Goje. “Now, this study reinforces that safety.”
The study looked at nearly 2,500 people who received one of the two mRNA COVID-19 vaccines (Pfizer or Moderna) before they got pregnant or before 20 weeks of pregnancy. The cases were pulled from the CDC’s v-safe COVID-19 Vaccine Pregnancy Registry, a separate program of its v-safe app where pregnant recipients of the vaccine can sign up to allow the CDC to track reactions in pregnant patients in the long term.
The results led the CDC to further bolster their recommendation that pregnant patients get vaccinated. In a statement, the organization said, “COVID-19 vaccination is recommended for all people aged 12 years and older, including people who are pregnant, breastfeeding, trying to get pregnant now, or might become pregnant in the future.”
The news is particularly encouraging when taken in the context of a previous study that showed a strong immune response to the vaccine in pregnant patients.
That previous study, published in late March by the American Journal of Obstetrics and Gynecology, looked at 131 patients: 84 were pregnant, 31 were lactating and 16 were not pregnant.
All of these patients received both doses of an mRNA COVID-19 vaccine (either Pfizer or Moderna). Once the vaccine took full effect, their antibodies were measured against those of 37 pregnant people who had been infected by COVID-19.
Not only did the study find that the vaccines generated a “robust” antibody response at the same rate as non-pregnant patients, but it also found that the level of antibodies in the vaccinated pregnant patients was higher than that of the infected pregnant patients.
Dr. Goje calls those results “exciting,” saying that it builds upon what we already knew. “What makes it so exciting is that some people had the idea that getting infected gave them the same immunity as the vaccine,” she says. “But this study tells us that no, you have a more robust immunity from the vaccine.”
There are two big reasons why the results of this study (and others) are so important.
First, it confirms there’s no risk to the health of either the patient or their fetus if they receive the vaccine. “Pregnant patients always want to make sure nothing is impacting the health of their babies,” Dr. Goje says.
Additionally, the data so far suggests that side effects caused by the vaccine in pregnant patients are comparable to non-pregnant patients. “From the data, we know the normal side effects that they experience, it does not put the fetus at risk,” she adds.
Dr. Goje also points out organizations like the American Society for Reproductive Medicine (ASRM) and the American College of Obstetricians and Gynecologists (ACOG) have repeatedly called for pregnant patients to be vaccinated.
“Doctors have stated emphatically, time and time again, that folks can get the vaccine and plan for a family,” she says. “They can get the vaccine and conceive, and even if they get the first dose and get pregnant, they can go ahead and get the second dose, too.”
In fact, with the release of the new study and the ongoing delta variant surge, ACOG put out a statement alongside nearly two dozen other organizations underscoring the essential need for pregnant patients to get vaccinated. The statement reads, in part, “With cases rising as a result of the Delta variant, the best way for pregnant individuals to protect themselves against the potential harm from COVID-19 infection is to be vaccinated.”
As for how to handle the side effects, again, there’s little difference between pregnant patients and non-pregnant patients. “Fever is something you don’t want in pregnancy but acetaminophen (i.e., Tylenol) is proven safe for pregnant patients to take at the prescribed dose,” she points out.
“There’s still much to learn from long-term studies, but staying hydrated and bed rest help recovery,” she adds.
Dr. Goje points to the CDC’s v-safe app and registry, important tools to track short- and long-term effects of the vaccines. The v-safe app allows anyone to use text messaging and web surveys to send their reactions to the vaccines to the CDC for collection; tens of thousands of vaccine recipients have already registered.
“So far, the CDC has documented that reactions and side-effects for pregnant patients are comparable to non-pregnant patients,’ Dr. Goje says. The registry, she adds, will allow researchers to better understand any differences over time.
The second big reason these results are so important is there’s more encouragement for pregnant patients to get vaccinated and help protect themselves, their child and others.
“Traditionally, pregnant patients have not been enrolled in clinical trials, including with the COVID-19 vaccines,” Dr. Goje says. “So there’s uncertainty for pregnant patients and it’s hard for some of them to make an informed decision about whether or not to receive the vaccine without having that data.”
The transparency in the data, especially this new research, though, is encouraging, she says. “Pregnant patients who declined earlier opportunities to receive the vaccine could become more comfortable,” she adds. “And it has to do with three things: transparency about the vaccine, the continuous availability of data from research and registries and educating patients about the vaccine.”
Any fears that the vaccine contains any part of a live virus are unfounded. The Moderna and Pfizer vaccines are mRNA vaccines, meaning they carry material that helps your body reproduce the “spike” protein found on the COVID-19 virus. That harmless protein is what triggers your body’s immune response. The vaccine does not cause an increased risk of infertility, miscarriage, stillbirth or birth defects.
Dr. Goje notes that it’s especially important for pregnant patients to receive the vaccine because they are at an increased risk for severe illness compared to non-pregnant patients. “They had increased rates of hospitalization, increased ICU stays and an increased risk of being intubated compared to non-pregnant patients, according to the CDC,” she says.
“The new study is extremely important at a time when we are seeing a surge of infections with the delta variant. It’s time to reinforce that vaccines save lives,” she adds.
And if a pregnant patient has comorbidities like diabetes or obesity, she says, that patient is at an even higher risk of severe illness. “Pregnant patients who get very sick also have an increased risk of having a pre-term birth which puts the baby at a higher risk of being put into the neonatal ICU,” she adds.
According to Dr. Goje, it’s important for pregnant patients to fully understand the data and the science behind the vaccine. “There’s a lot of misinformation out there but it’s getting better,” she says.
“Patients should always have an open discussion with their healthcare provider than to decline the vaccine outright,” she continues. “It’s okay to ask questions. Ask them, get them answered and, hopefully, embrace the protection both for mother and child.”