COVID-19 vaccines before and during pregnancy: What to know

Editor’s note: As what we know about COVID-19 evolves, so could the information in this story. Find our most recent COVID-19 blog posts here, and learn the latest in COVID-19 prevention at the Centers for Disease Control and Prevention.

There’s a lot of information to sort through during pregnancy, and it can be overwhelming to navigate. What medicine is safe to take for a cold, what does that weird feeling mean, and oh — what are the safest choices when you happen to be pregnant during a global pandemic?

One of the most important choices, says obstetrician/gynecologist Melissa Goist, MD, is whether to get the COVID-19 vaccine. 

“COVID-19 infection can cause such severe complications in pregnant people, especially, and that risk is high compared to the rare and mild known side effects of the vaccine,” she says. “Even with limited data, the vaccine has shown to be safe in pregnancy, and I have personally had many patients who have received the vaccine during pregnancy without any complications, as well as many who are now pregnant after obtaining the vaccine.”

Infectious disease specialist Nora Colburn, MD, MPH, also recommends the vaccine in these circumstances.

“As an infectious disease physician and a new mother, I urge every woman to get vaccinated against influenza and COVID-19 as soon as she can to protect herself and her baby,” Dr. Colburn says.  

The COVID-19 vaccine is surrounded by misinformation and sometimes-confusing data, and that’s exponentially true with internet chatter concerning getting the vaccine while pregnant.

So Dr. Goist and Dr. Colburn are here to explain what we know about the vaccine and why they support vaccination for their patients who are pregnant or might become pregnant.

Can COVID-19 vaccines cause infertility?

Dr. Colburn: There’s absolutely no evidence that any vaccine, including the COVID-19 vaccines, cause infertility in men or women. 

A recent study looked at pregnancy success rates in IVF (in vitro fertilization) in women who were vaccinated against COVID-19, those recently infected with COVID-19 and those who hadn’t been vaccinated or infected. The study found no differences in pregnancy among those three groups.

Are the vaccines safe in pregnancy?

Dr. Goist: Yes. Data from the Developmental and Reproductive Toxicity (DART) studies for all three available vaccines (Pfizer, Moderna and Johnson & Johnson) didn’t demonstrate any safety concerns in pregnancy. Data in the CDC’s v-safe post-vaccination health registry also didn’t demonstrate concerns in the more than 155,000 pregnant people registered, and they are no more likely to experience acute vaccine side effects than the non-pregnant population.

What are the risks of not getting vaccinated?

Dr. Goist: Pregnancy is associated with an increased risk of severe illness with COVID-19 infection, however. Pregnant people are more likely to need mechanical ventilation, three times as likely to be admitted to the ICU, and 1.7 times as likely to die of COVID-19 as non-pregnant people. 

We’re also seeing an increased risk of pregnancy complicated with COVID-19 infection, such as pregnancy loss, preterm labor, preterm birth and Cesarean delivery. When a baby is born early, they often have a prolonged stay in the neonatal intensive care unit (NICU). Preterm babies are at risk for many complications, including infection, brain bleeds, developmental delays, needing a ventilator and long-term respiratory complications.  

Dr. Colburn: The CDC recently reported results from a pregnancy registry of 2,456 pregnant people who received a COVID-19 vaccine either prior to conceiving or during pregnancy before 20 weeks gestation. There was no increased risk of miscarriage in this group compared to a reference population. (See more)

Dr. Goist: There are also 3,900 women being followed in a study devoted to pregnancy outcomes, and with 827 completed pregnancies at this time, there are so far no increased incidences of pregnancy complications.  

Can the fetus/baby get vaccine antibodies from its vaccinated mother?

Dr. Colburn: When a pregnant or breastfeeding mother gets any vaccine, her protective antibodies against the infection circulate throughout her body through the bloodstream. When pregnant, the mother’s blood stream connects with the fetus through the placenta, and protective antibodies can cross to the baby. This is why pregnant women are advised to get a Tdap (tetanus, diphtheria, pertussis) booster shot in their third trimester — the mother makes antibodies against pertussis, which then protect the baby from that disease.

Studies show that breastfeeding mothers have protective antibodies in their breastmilk, which can help protect their babies when they consume the milk.

Dr. Goist: A recent study showed that COVID-19 vaccine-induced IgG antibodies had transferred from mothers to their newborns. These studies aren’t yet completed, but they indicate a likely ability of the vaccine to give newborns some immune protection from COVID-19.

Can COVID-19 vaccines cause long-term side effects?

Dr. Colburn: In all vaccines, side effects show up within six to eight weeks of injection. There’s no evidence of any vaccination in history having long-term side effects (meaning many months/years).

COVID-19 vaccines also have been studied in humans since mid-2020, and more than 174 million people have been fully vaccinated in the United States alone. The vaccines continue to be closely monitored. 

The mRNA in the vaccine also degrades quickly through normal cellular processes, within a few hours or days after injection in your body.

Do the COVID-19 vaccines really work?

Dr. Colburn: The COVID-19 vaccines are incredibly effective at preventing severe COVID-19 disease as well as hospitalization and death. Efficacy data suggests that it’s equally effective in pregnant people.

In Ohio, about 98% of all COVID-19 hospitalizations and nearly 99% of COVID-19-related deaths are in unvaccinated people

How do we know the vaccines are safe in general, after such a quick development process?

Dr. Colburn: The COVID-19 vaccine has been through Phase 1, Phase 2 and Phase 3 trials without any shortcuts. Some worry that the trials were completed much more quickly than standard trials. Those trials were able to be completed quickly because there was so much funding and so many volunteers participating in the trials.

The trials have been monitored by the Data and Safety Monitoring Boards throughout their duration. The CDC continues to monitor for any adverse events through several active reporting and monitoring systems.

What does it mean for a vaccine to have emergency use authorization (EUA)?

Dr. Colburn: Emergency use authorization is a tool the U.S. Food and Drug Administration (FDA) uses to make medical products available quickly during the COVID-19 pandemic. The vaccines have gone through all three phases of clinical trials, and we have more than a year of data since the Phase 3 trials began in July 2020. The Pfizer vaccine has since received full FDA approval.

If the vaccine is safe for fetuses, why isn’t the vaccine approved for children yet?

Dr. Colburn: Approval for children 11 years and younger is expected in the coming months. Clinical trials for children (with Phases 1, 2 and 3) needed to be conducted for children just like for adult and teen populations. A large number of children were recruited in order to gather robust safety and efficacy data for that population.

Nora Colburn is an infectious disease physician at the Ohio State Wexner Medical Center and an assistant professor at the Ohio State College of Medicine.

Melissa Goist is a physician in obstetrics and gynecology at the Ohio State Wexner Medical Center and an assistant professor in the Ohio State College of Medicine.