How the COVID-19 Vaccine Affects the Menstrual Cycle: What We Know So Far


Has Your Menstrual Cycle Changed Since Getting Your COVID-19 Vaccine? You’re Not the Only One...

Fever, digestive upset and a wickedly sore arm are some of the side effects we’ve been told to expect from the vaccine. 

Menstrual irregularities, on the other hand, was not something on the collective radar when the vaccine first came out. And as it stands, the vaccine companies and the FDA are denying the vaccine has any impact on the menstrual cycle. However, there’s a wave of people coming forward to report that their menstrual cycles have been noticeably different after receiving their vaccine. If you’ve experienced this, you’re not alone. In fact, the reason I’m writing this article is because in my own clinical practice I started having women tell me: “My period was the heaviest it’s ever been,” or “my cramps were so bad I went to the hospital because I thought a cyst was bursting.” All out of the norm for what they’d usually experience with their periods, with the symptoms showing up the cycle after receiving the COVID-19 vaccination. Recently, I find myself telling client after client that they’re not the only ones. 

The impact on the menstrual cycle has gotten so much attention as of late, that 5 major medical institutions have been awarded a shared 1.67 million dollars to study it! (4) Dr. Kathryn Clancy, a researcher who has focused on uterine, ovarian and menstrual cycle health for decades, hopped on that research train right out of the gate. She noticed cycle irregularities first in herself when her period was “the heaviest it had ever been in (her) life” after receiving the COVID-19 shot. (3) Dr. Clancy decided to take it to social media to see if any one else was experiencing the same thing and her original tweet blew up with similar responses- people who experienced heavier or lighter bleeds, painful cramps, longer cycles, multiple bleeds in one month and/or breakthrough bleeding (even from people on long-acting reversible contraception, people on gender-affirming hormones, and postmenopausal people who were years and years out from their last period). (3) Since then she’s paired up with biological anthropologist and PhD, Katharine Lee, to research the connection between the vaccine and menstrual changes in an ongoing study, through which they’ve collected more than 140,000 reports from people who say they've noticed a change in their periods after vaccination. (3) It isn’t something that happens to everyone, that’s for sure, but if you’ve experienced anything like this, you’re not alone! 

If you want to contribute to their research and be a part of documenting this phenomenon, check out their online survey to participate.

The Gender Gap In COVID-19 Vaccine Research

One of the issues with the clinical trials done for the COVID-19 vaccine (along with a lot of medical research), is the lack of focus on how this medical intervention specifically impacts women’s bodies. (5) Because the priority was to get this vaccine out as soon as possible, the major focus was placed on investigating and reporting any “serious adverse reactions,'' and menstrual cycle changes didn’t fall under that category. More than that, menstrual irregularities weren’t even included as a potential listed “side effect” during the initial clinical trials. (3) Generally speaking, most women wouldn’t consider a heavier bleed or terrible cramps as a “serious adverse reaction”, which meant that these menstrual cycle changes went underreported and completely under the radar. 

Leading Theories: How Could the COVID-19 Vaccine Affect the Menstrual Cycle?

Immunity & The Uterus 

Did you know there are immune cells that run through the entire female reproductive system? In fact, immune cells play such an intricate role in some of our reproductive functions, like menstruation and pregnancy, that there’s a whole branch of medicine dedicated to it! These specialists are called reproductive immunologists. And according to a recent article published in Immunology Journal, it’s an exciting time to be one, because unlike the understanding we have of other mucous membranes, the female reproductive system is just starting to be explored in more depth. (2)  It’s about time, if you ask me! 

The science of immune cells can get pretty complex, pretty quickly, so for the purposes of simplicity we’ll keep this part brief. Essentially, scientists and researchers are suspecting that because the uterus mounts its own immune response to various stimuli, it may undergo its own changes and shifts as the body develops antibodies to respond to the COVID-19 virus. (2,4) No doubt we’ll have more answers soon with the ongoing research in the works!

What Else Could Be Going On? 

The vaccine may not be the only reason your period has gone awry. It’s well documented that other factors can affect the menstrual cycle: 

Stress is a huge menstrual cycle disruptor, and we know that COVID-19 has not been easy on us in the way of stress. Our sex hormones are particularly affected by cortisol, the stress hormone released when our nervous system kicks into “fight, flight or freeze” mode (the sympathetic response). Part of getting your cycle back on track, if this is the case for you, involves calming and nourishing the nervous system to encourage it to switch back into “rest and digest” mode (the parasympathetic response). Alongside other stress-reducing strategies, it’s good to remember that herbs can be a great way to support your immune system, decrease the stress load in your body and support hormone health. 

Also, it’s good to know that contracting COVID-19 itself has been linked to menstrual changes as well. One study conducted in China retroactively looked at women of child-bearing age diagnosed with COVID-19, and found that of “177 patients with menstrual records, 45 (25%) patients presented with menstrual volume changes, and 50 (28%) patients had menstrual cycle changes, mainly a decreased volume (20%) and a prolonged cycle (19%).” (1) 

How Long Will These Menstrual Irregularities Last? 

From what we know so far, there’s no indication that these cycle changes are permanent or long-lasting, according to Dr. Kathleen Jordan, a specialist in internal medicine and infectious disease and the senior vice president of Medical Affairs at Tia Clinic. (5) However, more research is needed, and as this phenomenon is studied in more depth, we’ll have more of an understanding of the time-frame associated with these cyclical changes. 

Important note: If there are persistent menstrual cycle changes, it’s definitely wise to get a check up from your family physician to rule out any underlying cause for concern. 

I hope this article was helpful along your health journey. 

With all of my herbal love, 


If you need support to get your menstrual cycle back on track with a little help from our herbal allies, I’ve got you! 



  1. Li, K., Chen, G., Hou, H., Liao, Q., Chen, J., Bai, H., Lee, S., Wang, C., Li, H., Cheng, L., & Ai, J. (2021). Analysis of sex hormones and menstruation in COVID-19 women of child-bearing age. Reproductive biomedicine online, 42(1), 260–267.

  2. Monin L., Whettlock E.M. & Male V. Immune responses in the human female reproductive tract. Immunology. 2020; 160: 106-115.

  3. National Public Radio (NPR): Why Reports Of Menstrual Changes After COVID Vaccine Are Tough To Study. 

  4. John Hopkins Medicine: COVID-19 NEWS: Study to Investigate Impacts of COVID Vaccines on Menstruation 

  5. Medical News Today: Can COVID-19 vaccines affect periods? 

  6. Dr. Aviva Romm: Has COVID-19 Caused a Wave of Pandemic Period Problems? 


  • Thanks Tianna! Super glad you found this information helpful!

  • I enjoyed the read, great information.


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