Think of COVID-19 vaccines and terms such as “medical miracle”, “scientific feat”, and “life-saver” come to mind. They have long been called the only way out of this pandemic. 

The efficiency and speed with which COVID-19 vaccines have had to be developed and deployed for use was a necessity in such times. And to worry about the side effects is natural and quite expected in this situation. 

Sore arm, fatigue, fever, headache, and body ache have been reported as common side effects after taking a COVID-19 vaccine. However, an unlisted and uncommon side effect of COVID-19 vaccines being reported by thousands of women across the globe is a change in their periods. 

Let’s find out more about this phenomenon. 

What Changes Have Been Reported? 

Women have reported various changes to their menstrual cycles, including:

  • Delayed periods.

  • Periods arriving earlier than expected.

  • Heavier blood flow during periods as compared to their usual cycles.

  • More painful periods than usual.

  • Periods lasting longer than their usual cycles. 

  • Postmenopausal women having breakthrough bleeding.

  • Women who have been on long-term contraceptives experiencing bleeding.

What Could be The Reasons Behind The Changes?

The reports of menstrual changes after COVID-19 vaccination do not appear to be limited to a specific type of COVID-19 vaccine. Also, these menstrual changes have not been reported by every woman who took the COVID-19 vaccine, just like not every vaccinated person gets a fever or headache.

The reports are being treated as anecdotal evidence (based on individual experiences or observations) at this stage and more research is needed to be able to conclude whether the vaccines are causing these effects, and if so, how. 

However, scientists have a few theories about the possible reason behind these menstrual changes after vaccination. 

Some suggest that any agent that triggers an immune response, such as the COVID-19 vaccine, could influence cellular processes in the uterus and ovaries, leading to changes in menstrual cycles. 

Some experts believe that the increased stress and the increased levels of stress hormone (cortisol) during these times, could be affecting periods. Cortisol is known to affect ovulation (release of eggs by women during their menstrual cycles) and reproductive hormone levels. So, stress, and not the vaccine, could be causing these menstrual changes. 

Vaccines depend on your immune system to initiate a response and produce antibodies that will protect you against the novel Coronavirus. So, another theory suggests that such side effects to the vaccine could be a sign of undetected autoimmune issues (when your immune system mistakenly considers a part of your body to be a foreign agent and attacks the healthy cells).

Experts also hypothesize that hormones are complex, and a woman’s unique hormonal makeup may play a role in the changes in menstruation post-vaccination.

Are These Changes Temporary?

According to available research, for most vaccinated women, changes to their menstrual cycles were temporary and their period returned to normal in the next cycle.

Experts advise anybody who experiences major or long-standing changes to their menstrual cycle to consult a doctor so that the cause behind the changes can be medically determined. 

Women who experience bleeding after menopause should also seek medical advice.

What Comes Next? 

Long-term research taking every factor under consideration is needed to assess the effect of COVID-19 vaccines on menstrual cycles so that women know what to expect when getting vaccinated. 

However, there is absolutely no evidence that COVID-19 vaccines adversely affect fertility in either sex. So, women should not use the information about these menstrual changes as a basis for their vaccine hesitancy. 

COVID-19 vaccination has immense benefits that far outweigh any risk. Get yourself vaccinated, and continue to maintain COVID-appropriate behaviour. 


References:

1. Male, V., 2021. Menstrual changes after covid-19 vaccination. BMJ, p.n2211.

2. NIH COVID-19 Research. 2021. COVID-19 Vaccines and the Menstrual Cycle | NIH COVID-19 Research. [online] Available at: <https://covid19.nih.gov/news-and-stories/covid-19-vaccines-and-menstrual-cycle> [Accessed 21 September 2021]. 


Disclaimer: This article is written by Practo for informational and educational purposes only. The content presented on this page should not be considered as a substitute for medical expertise. Please "DO NOT SELF-MEDICATE" and seek professional help regarding any health conditions or concerns. Practo will not be responsible for any act or omission arising from the interpretation of the content present on this page.