This was originally published in July 2021. Get the latest information on COVID-19 vaccines at COVID-19 Vaccines: Answers From Ob-Gyns.

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Dr. Mary Rosser and her family. Photos courtesy of Dr. Rosser.

I was thrilled when I got my first COVID-19 vaccine. It was Christmas Eve 2020, and I thought about how far we had come over the past year. I felt grateful to have a vaccine after all we had been through—all I had seen as an ob-gyn caring for so many sick patients.

It was like a weight had been lifted off my shoulders and I could finally take a deep breath. But my thoughts soon shifted to my family. I had been vaccinated early, as a health care professional. When could my two teenage girls get vaccinated as well? I wanted the same protection for them.

The first available vaccine was authorized for people 16 and older, but the doses were saved for priority groups. Then in May 2021, that same vaccine was authorized for anyone 12 and older, and by then it was widely available. My daughters just turned 16 and 17, and I’m happy to say they’re now both vaccinated.

We came to this decision together as a family. My husband and I had talked about the vaccines with our children for a long time, over many dinner table conversations. Here I’ll share what we discussed with our daughters—and what I say to my patients and other parents with questions about the vaccines.

How the Vaccines Work

My daughters have heard all sorts of myths about the vaccines. There’s chatter at school and on social media: How can we trust this new technology? Will the vaccines hurt your fertility?

I take these questions seriously, and I answer them only with scientific facts.

I start with a reminder that the science behind the vaccines is not new. The technology used in the mRNA vaccines has been in the works since the 1990s. And the process to develop the COVID-19 vaccines had all the same steps and safety checks as other vaccines.

Then I explain how the mRNA vaccines work. The COVID-19 virus has “spike proteins” on the outside surface. These spike proteins help the virus attach to and infect healthy cells in the body. The vaccines teach your body to make a similar protein that is harmless to you. This protein then causes your body to make antibodies that protect you from the coronavirus.

I like to draw it out on a napkin, to show exactly where the vaccine enters the cell. It does not enter the part of the cell where your DNA is. The vaccine does not touch your DNA at all.

After your cells use the vaccine to make antibodies, your cells break down the vaccine and get rid of it. You can read more about this whole process on the Centers for Disease Control and Prevention (CDC) website.

The Truth About Fertility

Dr. Rosser's daughters smile for the camera.
Dr. Rosser's daughters, 16 and 17, both received COVID-19 vaccines.

This basic understanding of how the vaccines work is the key to knowing why they could not affect your fertility.

Remember, the vaccines do not affect your DNA. They do not affect a pregnant woman’s placenta. They do not interact with anything in your body that could cause fertility problems.

The vaccines really are safe. I’ve read everything about the vaccines that I can get my hands on, and I feel certain that the vaccines will not affect my daughters’ ability to have children in the future.

For those who want to dig further into this topic, this article offers a detailed look at the science. It is from the American Society for Reproductive Medicine, which is our country’s leading group of infertility doctors.

And if you still have doubts, this study offers more proof that the vaccines do not cause infertility. The study found that women who got the COVID-19 vaccines were able to get pregnant at the same rates as women who had not gotten the vaccines.

Once you get pregnant, the vaccine will offer you crucial protection. Pregnancy increases your risk of severe illness if you get the virus. Getting a COVID-19 vaccine before or during pregnancy can protect you from severe illness and death.

Questions About Menstrual Periods

Some people ask me about whether the vaccines cause changes to your menstrual period. This is a complex question because there are many reasons why your period may change. During the pandemic, we have all felt higher levels of stress. Also, many of us have been eating more, moving less, and gaining weight. Stress and weight gain are just two examples of changes that can affect your menstrual cycle.

I reassure my patients that having one or two abnormal periods is not a sign of infertility. If you have an abnormal period, usually your periods will return to normal within 1 to 2 months. Temporary period changes are very common.

[2023 update: Studies have found small, temporary changes in menstrual periods after COVID-19 vaccination. These changes do not affect health or fertility. Get the latest on COVID-19 vaccines from ob-gyns.]

Weighing Risks and Benefits

With any vaccine, we ask ourselves: Are there any side effects that would outweigh the benefits of preventing disease?

Like other vaccines, the COVID-19 vaccines do have potential side effects. They may cause you to feel like you have the flu for a few days. The day after I got my vaccine, I didn’t feel well. But that was so much better than being on a ventilator. And, boy, do I feel that way about my kids.

There is also the question of heart problems (myocarditis and pericarditis) after vaccination. These are reactions where there is swelling in or around the heart muscle. These reports are rare, and they have mostly been seen in male teens and young adults age 16 and older. Most patients respond well to medicine and quickly feel better.

The CDC still recommends vaccination, even with that rare risk. Why? Because that risk is much smaller than the huge risk of COVID-19.

Teenagers can get seriously ill from COVID-19, just like anyone else. A 2021 study looked at teens who got COVID-19, had to go the hospital, and needed care in the intensive care unit (ICU).

About one in three teens in the study who were hospitalized did not have any underlying medical conditions. They had been perfectly healthy before the virus. That really spoke to me as a mom.

Thinking of My Children and Family

At the end of the day, we are trying to prevent serious illness and death. I thought about that and the fact that I just want to protect my children. I researched the science behind the vaccines and understood that they will not affect the health or future fertility of my daughters. I feel blessed that I was able to get them vaccinated.

Since my daughters have been vaccinated, they tell me they’re very relieved. They’ve been able to go to prom, celebrate the end of school with friends, and plan for summer jobs and sports. It will be a very different summer than last year.

Their grandparents are coming to visit soon, and this will be the first time we’ve seen them since before the pandemic. They’re in their 80s, and everyone’s vaccinated. We’re all beside ourselves with excitement.

I just can’t say enough about how freeing it feels for everyone in my family to be vaccinated. I hope your family can feel the same way.

Last updated: September 2023

Last reviewed: August 2023

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This information is designed as an educational aid for the public. It offers current information and opinions related to women's health. It is not intended as a statement of the standard of care. It does not explain all of the proper treatments or methods of care. It is not a substitute for the advice of a physician. Read ACOG’s complete disclaimer.

About the Author
Headshot of Dr. Mary Rosser.
Dr. Mary Rosser

Dr. Rosser is an obstetrician–gynecologist (ob-gyn). She also has a Ph.D. in endocrinology, the study of hormones. She is an assistant professor of obstetrics and gynecology at Columbia University Irving Medical Center, where she focuses on primary care and heart disease in women. She is an ACOG Fellow.