Jan 20, 2021 9:00 AM

Author: University of Utah Health Communications

The COVID-19 pandemic has created a lot of uncertainty and worries among vulnerable populations, including pregnant people. According to the Centers for Disease Control and Prevention (CDC), pregnant people are at an increased risk of severe illness from COVID-19 and death compared to non-pregnant people. Pregnant and breastfeeding people are encouraged to get vaccinated against COVID-19. While this group was not included in the inital COVID-19 vaccine trials, safety data of the benefits of vaccination has been growing. Torri Metz, MD, an associate professor in the Division of Maternal-Fetal Medicine at University of Utah, shares what is known about COVID-19 vaccines in pregnancy.

Risks of COVID-19 in Pregnancy

According to the CDC’s latest Morbidity and Mortality Weekly Report (MMWR), pregnant women:

  • Have an increased risk of ICU admission (10.5 vs 3.9 per 1,000 cases), mechanical ventilation (0.5% vs 0.3%), and risk of death. (1.5 vs 1.2 per 1,000 cases). These events are rare, but serious.
  • Have a 12.9% chance of a preterm birth, compared to 10.2% in the U.S. population in 2019.
  • Have a 2.6% chance of transmitting the virus to their babies. This is more likely after delivery than while the patient is pregnant.

According to a study conducted by University of California San Francisco about pregnant people with suspected COVID-19:

  • Out of the 592 people who tested positive, 20% reported a cough, 16% reported a sore throat, and 12% reported body aches.
  • The median time to symptom resolution was 37 days.
  • 25% of patients had persistent symptoms at eight weeks.


Under the Emergency Use Authorization (EUA) for the Pfizer/BioNTech vaccine, there are no restrictions based on pregnancy or breastfeeding status. Patients are recommended to have a discussion with their health care providers.

What is known about vaccines and pregnancy?

  • High-quality data exists for the safety and efficacy of other vaccines in pregnancy such an influenza and pertussis (tDaP).
    • Influenza: Pregnant patients are urged to get the flu shot every year because of increased complications if they get sick with the flu.
    • Pertussis (tDaP): The vaccination is given during pregnancy to protect the mother and allow antibodies to cross the placenta to protect the child and until the child can be vaccinated.
  • Live virus vaccines should not be used in pregnancy.
    • mRNA vaccines do not contain live virus.


mRNA vaccines are safe and effective in non-pregnant adults. Evidence does not suggest that mRNA crosses the placenta or into breast milk, but not enough data exists to know this with certainty.


  • 13 pregnant people were incidentally included in the trial; 6 were in the vaccine group.
    • No adverse effects of the vaccine were reported.
  • Preliminary data shows there is no effect on fertility or fetal/neonatal development.
  • Animal studies were reassuring.


  • 23 pregnant people were incidentally included in the trial; 12 were in the vaccine group.
    • No adverse effects of the vaccine were reported.
  • Animal data will be submitted to the FDA soon.

Although not much information is known about the effect of COVID-19 vaccine on pregnancy and breastfeeding, more data are anticipated. 


  • Pregnant people are at higher risk of severe illness if they acquire COVID-19.
  • Pregnant people who acquire COVID-19 are at higher risk of some adverse pregnancy outcomes such as preterm birth and cesarean delivery.
  • There is also a risk of transmission from the mother to the neonate.
  • COVID-19 vaccines are safe and effective in non-pregnant people.
  • Some patients may experience side effects after getting the vaccine.
  • Despite a lack of safety data on COVID-19 vaccination in pregnancy, there are no known risks, and pregnant people should be offered the vaccine.

Questions to consider:

  • Is the patient working in an area with high COVID-19 exposure?
  • Does the patient live with a lot of other individuals in their household?
  • Does the patient have underlying comorbidities that place them at increased risk of developing severe illness?


Pregnant people who decide to get the vaccine may experience side effects. According to the vaccine trials, 15% of patients had a fever after the second dose. Although reported fevers were not high, this side effect is the most worrisome for pregnant people. This group should treat fever with acetaminophen, which has been proven to effectively treat fevers.

There is no specific guidance as to when pregnant people should get vaccinated due to the lack of data. Timing of vaccination can be weighed along with the patient’s personal risk profile and should be discussed with a health care provider. Vaccination during pregnancy should be an informed personal choice. Pregnancy does not need to be avoided after vaccination.

covid-19 coronavirus vaccine mrna pregnancy breastfeeding obstetrics and gynecology

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