The truth behind COVID-19 vaccines and women’s health

Frequently asked questions about the vaccine and periods, fertility, breastfeeding and more


Misinformation is spreading on the Internet regarding the COVID-19 vaccines and how they may affect women’s health. We asked Clara Paik, clinic medical director of obstetrics and gynecology and the co-division director of University Women’s Health, some frequently asked questions about women’s health and the COVID shots (Pfizer, Moderna and Johnson & Johnson) currently available.

Clara Paik
Clara Paik

Do the COVID vaccines affect menstruation?

While many women have noted changes in their menstrual cycle after receiving the COVID vaccine, there is no evidence that the COVID-19 vaccine has any direct effect on menstruation. However, a woman’s ovulation and menstrual cycle can be affected by stress. Stress may be the reason for any effect on menstruation. We do not believe there is any physiologic reason why the vaccine itself would affect a woman’s menstrual cycle.

Will the COVID-19 vaccines affect mammogram results?

This is what the CDC recommends: If you are due for a mammogram and have been recently vaccinated for COVID-19, ask your doctor how long you should wait after vaccination to get your mammogram. People who have received a COVID-19 vaccine can have swelling in the lymph nodes (lymphadenopathy) in the underarm near where they got the shot. This swelling is a normal sign that your body is building protection against COVID-19. However, it is possible that this swelling could cause a false reading on a mammogram. Some experts recommend getting your mammogram before being vaccinated or waiting four to six weeks after getting your vaccine.

Do the COVID vaccines affect one’s fertility?

There is no evidence that the COVID-19 vaccines affect anyone’s fertility or cause infertility.

There is no evidence that the COVID-19 vaccines affect anyone’s fertility or cause infertility. Furthermore, there is no scientific theory for how the COVID-19 vaccines could cause fertility problems.

Are the COVID-19 vaccines safe for pregnant women?

Many pregnant women have received COVID vaccination without any problems. The National Institutes of Health (NIH) has started a study on COVID-19 vaccines during pregnancy and postpartum. Pregnant women are at an increased risk for COVID complications. We believe that the risks of COVID infection far outweigh the risks of receiving the vaccine. The Centers for Disease Control and Prevention (CDC), the American College of Obstetricians and Gynecologists (ACOG) and the Society for Maternal-Fetal Medicine (SMFM) agree that the COVID-19 vaccines should be offered to pregnant women who are eligible for vaccination.

Are the COVID-19 vaccines safe for breastfeeding women? Do the COVID vaccines provide protection to babies through breastmilk?

Yes, the COVID vaccines are safe for breastfeeding women. Research so far suggests that there may be some immunity provided to babies through breast milk, but this is not proven as of yet.

For more information about how the COVID-19 vaccine works and other frequently asked questions, visit our coronavirus website.