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What do we know so far about COVID-19 vaccines and their impact on menstruation?

This article was published on
April 27, 2021

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While several women are reporting temporary irregularities in their menstrual cycle, there is no scientific evidence available yet on the causal link between the COVID-19 vaccine and its effect on menstruation. Furthermore, there is no evidence that any of the COVID-19 vaccines could impact fertility or lead to a loss of fertility.   Getting vaccinated during one’s menstrual cycle does not pose any risks and the menstrual cycle has not been reported to have any effect on the vaccine efficacy. Vaccines should be taken as early as possible regardless of the timing of one’s menstrual cycle.

While several women are reporting temporary irregularities in their menstrual cycle, there is no scientific evidence available yet on the causal link between the COVID-19 vaccine and its effect on menstruation. Furthermore, there is no evidence that any of the COVID-19 vaccines could impact fertility or lead to a loss of fertility.   Getting vaccinated during one’s menstrual cycle does not pose any risks and the menstrual cycle has not been reported to have any effect on the vaccine efficacy. Vaccines should be taken as early as possible regardless of the timing of one’s menstrual cycle.

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What our experts say

After getting the COVID-19 vaccines some women report temporary changes in their menstrual cycle, including the duration, volume and timing, as well as discomfort.

The U.S. CDC does not note menstrual changes as a side effect of the vaccines. Menstrual changes were also not tracked in clinical trials. Therefore, there is no scientifically confirmed evidence that shows the vaccine causes irregularities in menstrual cycles. 

When a vaccine activates our immune system, it could temporarily affect immune cells that interact with the uterus, causing some irregularity. This may be because the lining of the uterus called the 'endometrium' is technically part of the immune system. However, more studies are needed to determine if this is the case. Menstrual irregularities could be due to many factors. Some studies indicate that COVID-19 itself could cause irregular menstrual cycles in some people.   While researchers are trying to understand the impact of vaccines on menstruation, it is important to know that there is no currently evidence that any of the vaccines cause fertility problems. The American College of Obstetricians and Gynecologists (ACOG), the American Society for Reproductive Medicine (ASRM), and the Society for Maternal-Fetal Medicine (SMFM) have released a joint statement confirming that is no evidence the vaccine could lead to a loss of fertility.

Context and background

Rumors on social media make claims about the risks of getting vaccinated during periods. Getting vaccinated during one’s menstrual cycle does not pose any risks, and no evidence shows that the menstrual cycle impacts how well the vaccine works. Vaccines should be taken as early as possible, regardless of the timing of one’s menstrual cycle.

Resources

  1. Medical Experts Continue to Assert that COVID Vaccines Do Not Impact Fertility (ACOG)
  2. Women are questioning whether the vaccine affects their menstrual cycle (NYT)
  3. Analysis of sex hormones and menstruation in COVID-19 women of child-bearing age (Reproductive Biomedicine Online)
  4. Lack of Data on Covid-19 Vaccines and Periods Inspired Two Feminist Scientists to Learn More (Medium)
  5. No, COVID-19 Vaccine Doesn’t Pose a Risk When Taken During Periods (The Quint)
  6. Does COVID-19 Wreak Havoc With the Menstrual Cycle? (Everyday Health)
  7. Can I Take The COVID Vaccine During My Periods, And Will It Affect My Cycle? (Women's Web)
  8. No, We Don’t Know if Vaccines Change Your Period (NYT)
  9. ‘No data’ linking Covid vaccines to menstrual changes, US experts say (The Guardian)
  10. Can the COVID Vaccine Affect Your Period? Some Women Say It's Changed Theirs—Here's What We Know Right Now (Health)

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