Getting your COVID-19 vaccine is so important that the last thing you want is to miss an appointment. There are good reasons to postpone your shot, such as testing positive for COVID-19, but being on your period isn’t one of them. This article looks at some of the reasons why it is OK to get the shot during your period.

Key Takeaways

  • People say they’ve seen changes in their periods during the COVID-19 pandemic, which is most likely because of stress.Research offers no evidence that the COVID-19 vaccine causes menstrual changes.Medical experts advise everyone to get the COVID-19 vaccine.

The concern over periods was first reported in February 2021 by the Israeli newspaper Haaretz, after some vaccinated Israelis reported having irregular periods. Other women took to social media to share their personal stories of period changes after the vaccine.

There’s currently no scientific evidence to support these stories or explain why they may be happening. Some experts, including anthropology professor Dr. Kate Clancy at the University of Illinois, have started research to find out more. Some 140,000 people have responded to Clancy’s survey about COVID-19 vaccines and menstrual changes.

Javeed Siddiqui, MD, an infectious disease specialist at TeleMed2U in California, tells Verywell that menstruation is not a reason to avoid or delay your vaccine. People with a history of severe allergic reactions to vaccines, though, should talk with a healthcare professional about them, he says.

In fact, experts say a COVID-19 infection presents a greater risk of long-term menstrual issues than the vaccines do. Researchers are also looking to see how the virus will shape new research on menstrual cycles.

Periods and the Immune System

The immune response is weaker at certain phases of the menstrual cycle. According to a 2018 review in the journal Trends in Ecology & Evolution, the body tones down the immune response to ensure the healthiest eggs are available to be fertilized by sperm.

The 2018 review suggests the body may be trading some immunity for a better shot at getting pregnant. This could explain why some people see flare-ups of diseases and a greater risk of infection during different parts of the menstrual cycle.

“The reason for the decreased immunity may be due to the need for less immune cells that would attack an implanted embryo," Kim Langdon, MD, an OB-GYN at Medzino based in Ohio, tells Verywell.

Langdon says there is little research on whether these changes in immunity across the menstrual cycle affect how well the vaccines will work, but she thinks it’s not likely.

Menstrual Cycle Problems and Long COVID

While more men than women have died from COVID-19, more women report long COVID-19 symptoms that persist for months.

What This Means For You

No matter what part of your menstrual cycle you are in, you should not skip out on the COVID-19 vaccine. The three FDA-approved or authorized vaccines have been proven safe and effective.

The risk of severe infection and menstrual problems from long COVID-19 far exceeds any unproven risk from the vaccine. If you have any concerns about immunization, you should speak with a trusted healthcare professional.

A few preprint studies—which did not go through peer review—found middle-aged White women with at least two preexisting medical conditions were more likely to have persistent COVID-19 symptoms.

Likewise, another study found that women under the age of 50 were five times less likely than men of the same age to say they weren’t fully recovered seven months after COVID-19 infection. The women in the study were seven times more likely to be short of breath and twice as likely to feel more fatigue compared to men.

How do periods come into play? “Women are indicating a change in their menstrual cycles [during long COVID]," Siddiqui says. “This change includes frequency, duration, flow, intensity, and pain level.”

Scientists are still researching why long COVID-19 affects the cycle, but stress may play a role. Langdon says any stress from an illness or a long quarantine could cause irregular menstrual cycles.

A February 2021 preprint study found 52.6% of women reported changes to their period during lockdowns. The menstrual cycle changes were linked to higher levels of family or personal stress. Stress from a job was also linked to increased bleeding during a period.

Another reason could be the coronavirus’s effect on reproductive hormones. A preprint study from China found people with menopause who had low estrogen and anti-müllerian hormone levels were less likely to have severe COVID-19 infection or need care in a hospital.

Given the health risks associated with COVID-19 infection, Siddiqui says that stopping the pandemic requires all hands on deck. “It is critical for all individuals who can receive [the] COVID vaccine," Siddiqui says. “We need you; we need you to get vaccinated.”

Summary

There are a lot of questions about COVID-19 and people’s periods, but the truth is that medical science doesn’t yet have as many answers. Many women report menstrual changes after either a COVID-19 infection or getting the vaccine, but researchers are still working to see why.

Recap

Thousands of women have reported changes in the frequency, flow, and other qualities of their periods during the COVID-19 pandemic. Some of their concerns have been linked to stress, rather than a COVID infection or vaccine side effects.

What they do agree on is that getting your period is no reason to avoid getting the vaccine.

A Word From Our Medical Reviewer

Of the many things to consider when getting the vaccine, the connection of the menstrual cycle is a recent topic. Although the case reports are interesting, we do not have enough to tell us whether this is a causal relationship or a direct link. Right now, receiving the vaccine is of utmost importance and millions of women are receiving the vaccines daily. Your period should not stop you from getting vaccinated.

What we do know with certainty is that physiologically, the parts of the brain associated with fever induction and inflammation also are the same parts of the brain that control the hormonal regulation of the menstrual cycle. Hormones do have the ability to turn inflammatory responses on and off. Therefore, there is good cause for more studies devoted to women’s vaccine outcomes and reproductive health. 

The information in this article is current as of the date listed, which means newer information may be available when you read this. For the most recent updates on COVID-19, visit our coronavirus news page. 

Dr. Shepherd is board-certified in obstetrics-gynecology and is affiliated with Baylor University Medical Center in Dallas, Texas. Dr. Shepherd appears regularly as an expert on Good Morning America, The Today Show, and more.