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COVID-19 and the Menstrual Cycle

R, 29, had just recovered from a mild Covid infection with a scratchy throat and cough 2 weeks ago. She was shocked to experience severe abdominal pain during the first and second days of her first menstrual period after recovering from the illness. She was also passing out lots of blood clots. Prior to her Covid infection, her periods had been very regular, occurring every 28 to 30 days, without any symptoms.

During the past 2 years, some women have reported changes in their menstrual cycles for months after the infection. Others have also noticed disruptions in their menses following Covid vaccination.

What are some of the changes to women’s periods following covid infection?

They include:

  • Heavy bleeding

  • Reduced amount of bleeding

  • Intermenstrual bleeding(bleeding between periods)

  • No menstruation

  • Shorter or longer cycle

  • Acute abdominal pain

How does Covid virus affect menstrual cycle?

The menstrual cycle is controlled by a number of hormones regulated by the hypothalamus and pituitary gland in the brain together with the ovaries. In severe illness, such as Covid, the body would temporarily stop ovulation and channel the energy towards fighting off the infection. The menses will thus stop for a while and return to normal after the patient recovers.

Covid can also cause massive inflammatory responses in the body, which in turn will cause disturbances in menses. It has also been suggested that the virus may enter the ovarian cells directly and affect the production of sex hormones.

A study published in 2021 comparing the menstrual cycles of 237 patients with COVID to their cycles from beforehand found that 18% of mildly ill and 21% of severely ill patients had longer cycles with reduced amounts of menstrual flow. The suppression of ovarian function however is only transient and menses quickly returns to normal within 2 months after recovery.

Can Covid vaccination affect menstrual cycle?

Women vaccinated against COVID-19 have reported disruption of their menstrual cycle. An earlier study published in the British Medical Journal (BMJ) was unable to find a conclusive connection. A recent study, however, looked at two groups of women (about 2,400 women who received vaccines and about 1,600 who remained unvaccinated) over six menstrual cycles to see how vaccination changed cycle length. Overall, vaccination was associated with an increase of about one day in the cycle length.

Emerging data also suggest that patients with endometriosis and PCOS are more likely to have the cycles disrupted by the vaccines though the effects may be temporary.


It appears that COVID infection and vaccines can cause disruption in the menstrual cycle. Stress caused by the pandemic may possibly also play an important role in causing such disturbances. Fortunately, studies so far have suggested that these changes appear to be transient and menstrual cycles seemingly return to normal after a few months for many women.

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