COVID-19 Vaccination During Pregnancy and Breastfeeding: What to Know

What We Know So Far About the COVID-19 Vaccination

2020 is a year that future generations will read about in the history books. A global pandemic flooded through all of our lives and overwhelmed the healthcare industry. The impact of COVID-19 will forever be a part of our lives; however, as we continue to battle the virus today, many uncertainties remain. One uncertainty impacts a large population of women; those who are pregnant and/or breastfeeding. Consistent with historical vaccination trials, this population was excluded from COVID-19 vaccine clinical trials. This reality has placed many in limbo, self-researching when and if to become vaccinated – often leading to partial and/or non-evidence based information from unreputable sources. Close collaboration with primary care providers and OBs is strongly encouraged when considering vaccination for these women.

How the COVID-19 Vaccine Works

There are two vaccines currently available under the Food and Drug Administration (FDA) Emergency Use Authorization (EUA): Pfizer and Moderna.

• Pfizer-BioNtech mRNA Vaccine: For use in individuals age 16 years and older as a 2-dose regimen given 3 weeks (21 days) apart.
• Moderna mRNA Vaccine: For use in individuals age 18 and older as a 2-dose regimen given 1 month (28 days) apart.

These vaccines are messenger RNA, or mRNA, vaccines. The way in which they provide immunity varies from vaccines we are typically accustomed to receiving. Many vaccines contain a weakened or inactivated piece of the virus that triggers an immune response, however, this is not the case with these early COVID-19 vaccines. Instead, they teach the cells how to make a protein that triggers an immune response by producing antibodies. This protein, known as a spike protein, is found on the surface of the virus that causes COVID-19. According to the CDC, after the protein piece is made, the cell breaks down the instructions and gets rid of them. The cell then displays the protein piece on its surface. Our immune systems recognize that the protein doesn’t belong there and begin building an immune response and making antibodies, like what happens in natural infection against COVID-19.  At the end of the process, our bodies have learned how to protect against future infection (2020). The New York Times published an easy-to-interpret article breaking down this mRNA vaccine.

Two additional vaccines are on the horizon – Johnson & Johnson and AstraZeneca. Both use a more traditional method to create immunity, including using an inactivated part of the virus that causes COVID-19. Clinical trials are well underway and request for EUA from the FDA will not be far off.

What Pregnant and Breastfeeding Mothers Should Know

Like most clinical trials, exclusion criteria prevented pregnant women from participating in the early COVID-19 vaccine trials. The use of these new vaccines in breastfeeding mothers has not been well studied.  With additional and ongoing trials, it is anticipated that more information will arise on safety within these populations. Unfortunately, there are no simple answers to many of the questions out there right now. As this is an evolving situation, here are the most up to date recommendations from professional and reputable organizations:

American College of Obstetricians and Gynecologists (ACOG)

According to their clinical practice advisory recommendations (2020):

ACOG recommends that COVID-19 vaccines should not be withheld from pregnant individuals who meet criteria for vaccination based on the Advisory Committee on Immunization Practices (ACIP)-recommended priority groups.

COVID-19 vaccines should be offered to lactating individuals similar to non-lactating individuals when they meet criteria for receipt of the vaccine based on prioritization groups outlined by the ACIP.

Individuals considering a COVID-19 vaccine should have access to available information about the safety and efficacy of the vaccine, including information about data that are not available. A conversation between the patient and their clinical team may assist with decisions regarding the use of vaccines approved under EUA for the prevention of COVID-19 by pregnant patients.  Important considerations include:

• The level of activity of the virus in the community
• The potential efficacy of the vaccine
• The risk and potential severity of maternal disease, including the effects of disease on the fetus and newborn
• The safety of the vaccine for the pregnant patient and the fetus

While a conversation with a clinician may be helpful, it should not be required prior to vaccination as this may cause unnecessary barriers to access.

Infant Risk Center

The Infant Risk Center at Texas Tech University Health Sciences Center (2020) states that most of the COVID-19 vaccines are probably going to be quite safe for breastfeeding mothers and their infants. In these situations, physicians and breastfeeding mothers in consult will have to weigh the relative risks of the vaccine to that of the infection with Coronavirus in that specific mother. At this time, none of the new vaccines are live or infectious. They are made of very few ingredients: the fragile mRNA, some fats to protect the mRNA long enough for your body to respond to it, and some salts to make the shot sting less. There are NO preservatives!

As for breastfeeding, little or none of these vaccine components would ever reach the milk compartment, or even be transferred into human milk.  Even if they were, they would simply be digested like any other protein by the infant. It is their opinion that the present group of vaccines are probably going to be quite safe for breastfeeding mothers. The infant may even gain a small amount of maternal IgG in the breast milk, which may be beneficial.

At this point, since many of the new vaccines do not contain live viruses and are not infectious, the Infant Risk Center supports the opinion from the Society for Maternal-Fetal Medicine (SMFM) and the American College of Obstetricians and Gynecologists (ACOG) that most COVID-19 vaccines are probably safe for pregnant women. Ultimately, the risk of infection in that patient must be weighed against the probable minimal risk of the vaccine. Navigate to their statements by clicking the hyperlinks above.

Centers for Disease Control and Prevention (CDC)

According to the CDC (2021), getting vaccinated is a personal choice for people who are pregnant. People who are pregnant and part of a group recommended to receive COVID-19 vaccine, such as healthcare personnel, may choose to be vaccinated. A conversation between pregnant patients and their clinicians may help them decide whether to get vaccinated with a vaccine that has been authorized for use under Emergency Use Authorization (EUA). While a conversation with a healthcare provider may be helpful, it is not required prior to vaccination.

There are no data on the safety of COVID-19 vaccines in lactating women, including the effects of mRNA vaccines on the breastfed infant or on milk production/expression. mRNA vaccines are not thought to be a risk to the breastfeeding infant. People who are breastfeeding and are part of a group recommended to receive a COVID-19 vaccine, such as healthcare personnel, may choose to be vaccinated.

Academy of Breastfeeding Medicine (ABM)

According to a recent statement released by the Academy of Breastfeeding Medicine (2020), many lactating individuals fall into categories prioritized for vaccination, such as front-line healthcare workers. The Academy of Breastfeeding Medicine does not recommend cessation of breastfeeding for individuals who are vaccinated against COVID-19. Individuals who are lactating should discuss the risks and benefits of vaccination with their healthcare provider, within the context of their risk of contracting COVID-19 and of developing severe disease. Healthcare providers should use shared decision making in discussing the benefits of the vaccine for preventing COVID-19 and its complications, the risks to mother and child of cessation of breastfeeding, and the biological plausibility of vaccine risks and benefits to the breastfed child.

They provide additional details about the structure of the vaccine and its anticipated impact during lactation: “During lactation, it is unlikely that the vaccine lipid would enter the blood stream and reach breast tissue. If it does, it is even less likely that either the intact nanoparticle or mRNA transfer into milk. In the unlikely event that mRNA is present in milk, it would be expected to be digested by the child and would be unlikely to have any biological effects” (ABM, 2020).  Read the full statement.

Food and Drug Administration (FDA)

Found under both Pfizer and Moderna FAQ pages on the FDA website (2021), they state, “while there have been no specific studies in these groups, there is no contraindication to receipt of the vaccine for pregnant or breastfeeding women. Pregnant or breastfeeding women should discuss potential benefits and risks of vaccination with their healthcare provider.”

March of Dimes

A full statement from the March of Dimes was released in early January 2021 regarding COVID-19 vaccination and pregnant and breastfeeding people. A summary of this statement includes the following:

• Impact from the transmission of SARS-CoV-2, the virus that is causing the COVID-19 pandemic, includes prioritizing pregnant individuals at high risk and will require a number of strategies for prevention, including immunization.
• The COVID-19 vaccine should not be withheld from pregnant and lactating people who choose to be vaccinated.
• For those pregnant and lactating individuals who may be concerned regarding the unavailability of further safety data, a conversation with their healthcare provider may help them with the decision-making process but is not required prior to vaccination.
• Pregnant and lactating individuals who receive the vaccine are encouraged to enroll in safety monitoring systems, such as the CDC’s V-safe program which is a smartphone-based, after-vaccination health checker.
• The Federal government and pharmaceutical companies should work together to enroll pregnant and lactating women in clinical trials and ensure surveillance studies monitor vaccination within individuals expected to receive it.

World Health Organization (WHO)

The World Health Organization (WHO) released Interim recommendations for use of the Moderna mRNA-1273 vaccine against COVID-19 on January 25, 2021. Directly taken from this release are their recommendations for pregnant and lactating women as it relates to the Moderna vaccine:

Pregnant Women

Pregnant women are at higher risk of severe COVID-19 compared with women of childbearing age who are not pregnant, and COVID-19 has been associated with an increased risk of preterm birth. The available data on mRNA-1273 vaccination of pregnant women are insufficient to assess vaccine efficacy or vaccine-associated risks in pregnancy. However, it should be noted that the mRNA-1273 vaccine is not a live virus vaccine, and the mRNA does not enter the nucleus of the cell and is degraded quickly.

Developmental and reproductive toxicology (DART) studies in animals have not shown harmful effects in pregnancy. Further studies are planned in pregnant women in the coming months. As data from these studies become available, recommendations on vaccination will be updated accordingly. In the interim, WHO recommends not to use mRNA-1273 in pregnancy, unless the benefit of vaccinating a pregnant woman outweighs the potential vaccine risks, such as in health workers at high risk of exposure and pregnant women with comorbidities placing them in a high-risk group for severe COVID-19. Information and, if possible, counselling on the lack of safety and efficacy data for pregnant women should be provided.

WHO does not recommend pregnancy testing prior to vaccination. WHO does not recommend delaying pregnancy following vaccination.

Lactating Women

Breastfeeding offers substantial health benefits to lactating women and their breastfed children. Vaccine efficacy is expected to be similar in lactating women as in other adults. However, there are no data on the safety of COVID-19 vaccines in lactating women or on the effects of mRNA vaccines on breastfed children. As the mRNA-1273 vaccine is not a live virus vaccine and the mRNA does not enter the nucleus of the cell and is degraded quickly, it is biologically and clinically unlikely to pose a risk to the breastfeeding child. On the basis of these considerations, a lactating woman who is part of a group recommended for vaccination, e.g. health workers, should be offered vaccination on an equivalent basis. WHO does not recommend discontinuing breastfeeding after vaccination.

United Kingdom Government

According to the UK Government (2021), although the available data do not indicate any safety concern or harm to pregnancy, there is insufficient evidence to recommend the routine use of COVID-19 vaccine during pregnancy.  They do go on to say that consideration should be taken in situations where the risk of exposure to SARS-CoV-2 infection is high and cannot be avoided, or where the woman has underlying conditions that put them at very high risk of serious complications of COVID-19.

As for breastfeeding mothers, they state there is no known risk associated with giving non-live vaccines whilst breastfeeding. The Joint Commission of Vaccination and Immunisation (JCVI) advise that breastfeeding women may be offered vaccination with either the mRNA or traditional vaccines when they become available.  The developmental and health benefits of breastfeeding should be considered along with the woman’s clinical need for immunization against COVID-19, and the woman should be informed about the absence of safety data for the vaccine in breastfeeding women.

To Summarize and Conclude:

As I mentioned early on, there are currently no easy answers to questions related to the COVID-19 vaccine and pregnant or lactating mothers.  I hope this summarization of current recommendations was helpful in either making an informed decision or supporting someone through their decision making.  Many valuable resources can be found on the Medela COVID-19 microsite, for both healthcare professionals and moms.   All recommendations do suggest that until the COVID-19 vaccination is recommended for all pregnant and breastfeeding mothers, it is important to prevent the disease with precautionary measures.  

WHO, UNICEF, and the CDC recommend that mothers continue breastfeeding their newborns, given that clinical evidence clearly shows the benefits of breastfeeding outweigh the risks of infection. If you are breastfeeding and COVID-19 suspected or positive, practice the 3 Ws as recommended by UNICEF: WEAR a mask during feeding, WASH your hands with soap before and after touching your baby, and WIPE and disinfect surfaces regularly (2021).

Although we have already learned so much in a very short period of time, there is clearly considerably more to learn as it relates to COVID-19, the vaccine, and its impact on pregnant and lactating women.  Early research has provided us a starting point; however, a clear path forward is still forthcoming. As continued research is conducted, clearer recommendations can be anticipated. An exciting research study is underway at the University of California San Diego School of Medicine. They are working to determine if the COVID-19 vaccination could not only protect the mother, but also their breastfed infants through antibodies in the milk.  Read more about their exciting study here!

Disclaimer

The information and materials provided on this website do not, and are not intended to, constitute medical advice. Please consult with your primary care physician for medical advice.  All information available on this site is for general informational purposes only and may not include the most up-to-date information. Medela reserves the right to supplement this website at any time or to change or delete any information or materials on this website. This website contains links to other third-party websites. Such links are only for the convenience of the reader, user or browser; Medela does not recommend or endorse the contents of the third-party sites.

References

Academy of Breastfeeding Medicine (2020). Considerations for COVID-19 Vaccination in Lactation. Retrieved from bfmed.org/abm-statement-considerations-for-covid-19-vaccination-in-lactation?fbclid=IwAR3NyQAeTX7GlDPNLsKUL5dom_5eGGEhuOC90mKSehQhub3tCTqcHzN_1AU

Centers for Disease Control and Prevention (2020). Understanding mRNA COVID-19 Vaccines. Retrieved from cdc.gov/coronavirus/2019-ncov/vaccines/different-vaccines/mrna.html

Centers for Disease Control and Prevention (2021). Vaccination Consideration for People who are Pregnant or Breastfeeding. Retrieved from cdc.gov/coronavirus/2019-ncov/vaccines/recommendations/pregnancy.html

Corum, J., & Zimmer, C. (2021, January 21). How the Pfizer-BioNTech Vaccine Works. The New York Times. Retrieved from nytimes.com/interactive/2020/health/pfizer-biontech-covid-19-vaccine.html

Family Larsson Rosenquist Foundation (2021). COVID-19 Vaccination: Can it Protect Breastfed Children as Well? Retrieved from larsson-rosenquist.org/en/activities/news/vaccine-breastfeeding/

Infant Risk Center At Texas Tech University Health Sciences Center (2020). COVID-19 Vaccine in Pregnancy and Breastfeeding.  Retrieved from infantrisk.com/covid-19-vaccine-pregnancy-and-breastfeeding

March of Dimes (2021). March of Dimes Statement on COVID-19 Vaccination and Pregnant and Lactating People. Retrieved from marchofdimes.org/news/covid19-vaccine-statement.aspx

Medea (2021). COVID-19: Information concerning pregnant and breastfeeding mums. Retrieved from medela.com/breastfeeding/mums-journey/covid-19-information-concerning-breastfeeding

Public Health England (11 January 2021). COVID-19 vaccination programme: Information for healthcare practitioners. (V 3.1). Retrieved from assets.publishing.service.gov.uk/government/uploads/system/uploads/attachment_data/file/951155/COVID-19_vaccination_programme_guidance_for_healthcare_workers_11_January_2021_V3.1.pdf

The American College of Obstetricians and Gynecologists (2020). Coronavirus (COVID-19), Pregnancy, and Breastfeeding: A Message for Patients. Retrieved from acog.org/womens-health/faqs/coronavirus-covid-19-pregnancy-and-breastfeeding

The American College of Obstetricians and Gynecologists: Clinical (2021). Vaccinating Pregnant and Lactating Patients against COVID-19. Retrieved from acog.org/clinical/clinical-guidance/practice-advisory/articles/2020/12/vaccinating-pregnant-and-lactating-patients-against-covid-19

U.S. Food & Drug Administration (2021). Moderna COVID-19 Vaccine Frequently Asked Questions. Retrieved from fda.gov/emergency-preparedness-and-response/mcm-legal-regulatory-and-policy-framework/moderna-covid-19-vaccine-frequently-asked-questions

U.S. Food & Drug Administration (2021). Pfizer-BioNTech COVID-19 Vaccine Frequently Asked Questions. Retrieved from fda.gov/emergency-preparedness-and-response/mcm-legal-regulatory-and-policy-framework/pfizer-biontech-covid-19-vaccine-frequently-asked-questions

World Health Organization (2021). Interim recommendations for use of the Moderna mRNA-1273 vaccine against COVID-19. Retrieved from who.int/publications/i/item/interim-recommendations-for-use-of-the-moderna-mrna-1273-vaccine-against-covid-19

World Health Organization (2021).  Who can take the Pfizer-BioNTech COVID-19 vaccine?. Retrieved from who.int/news-room/feature-stories/detail/who-can-take-the-pfizer-biontech-covid-19--vaccine