Women are facing unique challenges in the COVID-19 pandemic, a topic we discussed in an earlier article¹. Worldwide rollout of COVID-19 vaccines that aims to protect the general public leads to another tough decision: should pregnant women and breastfeeding mothers receive vaccines? These women are typically not studied in clinical trials^2,3. This is also true for COVID-19 vaccine development: following governmental guidelines, current major manufacturers of COVID-19 vaccines, such as Pfizer/BioNTech, left out pregnant women and breastfeeding mothers from their clinical trials so far^4,5.

Although diverse participants in clinical trials are important⁶, exclusion of pregnant women and breastfeeding mothers is based on medical and ethical concerns. Considered a vulnerable group, pregnant women undergo significant changes in their bodies to nurture a new life. The complex biological changes in pregnant women can potentially affect their responses to drugs or vaccines. Moreover, any influence on the mother might be passed to the developing baby.

To understand a disease and its cures and vaccines, non-clinical research plays a vital role in evaluating what clinical trials do not focus on. In other words, non-clinical research not only paves the way to clinical research but can also fill in the knowledge gaps not covered by clinical trials. For COVID-19, a significant gap lies in the short- and long-term effects of disease treatments and vaccines on people excluded from clinical trials. However, limited non-clinical COVID-19 research exists to understand how the coronavirus and the new vaccines behave in pregnant or breastfeeding women. This is a gap that has been widened in this pandemic by the fact that most efforts are diverted to treating and preventing the disease that has swept the world so unexpectedly and rapidly. Moreover, although clinical trials conducted on tens of thousands of volunteers have shown that the approved vaccines are safe and efficient in the short-term, there are not yet enough data for evaluating their long-term impacts; currently authorized vaccines are developed in less than a year, and mass vaccination began just about 2 months ago.

So with mixed excitement and anxieties, all mother-to-be and new mothers are left with a huge dilemma: should I or should I not get the COVID-19 vaccine⁷? Some women chose to postpone their family plan or end unplanned pregnancies through contraceptives and safe abortions. However, this is not an option for women in some countries because of re-allocation of most resources for COVID-19 or law restrictions^8,9. Even among scientists and healthcare professionals —including doctors who are expecting newborns themselves⁷—this is a dividing topic⁴. Insufficient data on the new vaccines in pregnant women and breastfeeding mothers makes it unclear whether it is safe for them to be vaccinated or whether the vaccines act equally effectively on them. It also makes it difficult for experts to completely agree on the best recommendations.

Some experts advise against vaccination for pregnant and breastfeeding women until more data become available. Others believe that, as no data by far has raised safety concern about COVID-19 vaccination in pregnant and breastfeeding women, the benefit of protection against COVID-19 outweighs the risk of serious complications caused by the disease^10,12. In particular, Pfizer/BioNTech and Moderna’s vaccines are RNA vaccines that are made of just fragments of the viral genetic material, not live viruses^13,14. In other words, these vaccines cannot cause COVID-19 (see Myths and Facts about COVID-19 Vaccines in ¹⁵). Clinical trials involving many participating volunteers (43,448 and 30,420 for Phase 3 clinical trials for Pfizer/BioNTech and Moderna, respectively) have also proven the safety of these vaccines^5,16. Importantly, the clinical trial data have been evaluated by “groups independent from the pharmaceutical companies that make the drugs and … have no stake in the vaccine development or commercialization¹⁷.”

As of today, decisions about whether pregnant women should get vaccines vary from country to country. In the U.K., pregnant women are advised not to be vaccinated for now unless they have other underlying health conditions that put them at risk for severe COVID-19 symptoms¹⁸. In the U.S., the decision is left to pregnant women and breastfeeding mothers themselves^10,11. Regardless of the recommendations, all guidelines and experts strongly encourage consulting with medical professionals to weigh the risks and benefits before getting the vaccine, especially if other health issues put you at a higher risk for complications. It is also important to learn about evolving recommendations for COVID-19 vaccines only from credible sources.

While wealthy countries begin to distribute vaccines to the general public, underdeveloped countries with fewer resources are already in a disadvantaged position to secure enough vaccines for their residents. Unfortunately, over time, the gap between underdeveloped nations and the wealthy ones is estimated to grow. This is another important topic that we will cover in a future post.

Disclaimer: The goal of this article is to present facts from credible sources unaffiliated with industries. It does not replace professional consultation with medical specialists. Guidelines on COVID-19 vaccines are quickly evolving, so seek professional advice for up-to-date information when making personal choices. The author declares no conflict of interest, bias, or personal views.

Further Readings 

1. Silva, B. “COVID-19 and Gender Equality – Selected Challenges for the Achievement of SDG 5.” COVID-19 Action Hub, United People Global. 2021. https://bit.ly/2MztbML

2. “Research Gaps Leave Doctors Guessing About Treatments for Pregnant Women.” National Public Radio (NPR). 2018. https://n.pr/2XDJqu0

3. Kobie, N. “There’s a Big Data Gap When It Comes to Vaccines and Pregnancy.” WIRED UK. 2021. https://bit.ly/2N10k3Q

4. Mandavilli, A., & Rabin, R. C. “Pregnant Women Get Conflicting Advice on COVID-19 Vaccines.” The New York Times. 2021. https://nyti.ms/36LhsBA5.

5. Polack, F. P., Thomas, S. J., Kitchin, N., Absalon, J., Gurtman, A., Lockhart, S., Perez, J. L., Pérez Marc, G., Moreira, E. D., Zerbini, C., Bailey, R., Swanson, K. A., Roychoudhury, S., Koury, K., Li, P., Kalina, W. V., Cooper, D., Frenck, R. W., Hammitt, L. L., Gruber, W. C. 2020. Safety and Efficacy of the BNT162b2 mRNA Covid-19 Vaccine. New England Journal of Medicine, 383(27), 2603–2615. https://doi.org/10.1056/nejmoa2034577

6. Barron, D. “Diversity Dilemma.” Reuters Events Pharma. 2017. https://bit.ly/38FXKbV

7. Gordon, M. “COVID Vaccine During Pregnancy? Even Doctors Struggle With This Question.” The New York Times. 2020. https://nyti.ms/38Hbxii

8. Ford, L. “COVID-19 Threatens Access to Abortions and Contraceptives, Experts Warn.” The Guardian. 2020. https://bit.ly/35z4o1y

9. Munyeza, B. “The Impact of Restrictive Abortion Laws on Abortion Statistics.” Safe2choose. 2021. https://bit.ly/3oGwLT5

10. Mandavilli, A. “Pregnant and Breastfeeding Women May Opt to Receive the Vaccine.” The New York Times. 2020. https://nyti.ms/3bxpyRz

11. “Vaccination Considerations for People who are Pregnant or Breastfeeding.” Centers for Disease Control and Prevention. 2021. https://bit.ly/3aCgw3B

12. Goldfarb, I. T. “Wondering About COVID-19 Vaccines If You’re Pregnant or Breastfeeding?” Harvard Health Blog. 2021. https://bit.ly/2NYR2pk

13. Corum, J., & Zimmer, C. “How the Pfizer-BioNTech COVID-19 Vaccine Works.” The New York Times. 2021. https://nyti.ms/3nH5Www

14. Corum, J., & Zimmer, C. “How Moderna’s COVID-19 Vaccine Works.” The New York Times. 2021. https://nyti.ms/3oIeLrx

15. “Myths and Facts about COVID-19 Vaccines.” Centers for Disease Control and Prevention. 2021. https://bit.ly/3jlqU3u.

16. Baden, L. R., El Sahly, H. M., Essink, B., Kotloff, K., Frey, S., Novak, R., Diemert, D., Spector, S. A., Rouphael, N., Creech, C. B., McGettigan, J., Khetan, S., Segall, N., Solis, J., Brosz, A., Fierro, C., Schwartz, H., Neuzil, K., Corey, L., Zaks, T. 2021. Efficacy and Safety of the mRNA-1273 SARS-CoV-2 Vaccine. New England Journal of Medicine, 384(5), 403–416. https://doi.org/10.1056/nejmoa2035389

17. “What’s Different About Messenger RNA (mRNA) Vaccines for COVID-19?” Memorial Sloan Kettering Cancer Center. 2021. https://bit.ly/36Gn687

18. “COVID-19 Vaccination: A Guide for Women of Childbearing Age, Pregnant or Breastfeeding.” GOV.UK. 2021. https://bit.ly/3oIBovM