Covid: a large study confirms the impact of the vaccine on the menstrual cycle

in collaboration with

Dr Odile Bagot (Gynecologist-obstetrician)

It is, to date, the most in-depth study on a subject that is still little studied: the effects of the vaccine against covid on the menstrual cycle in women. The University of Illinois at Urbana-Champaign has just published in the journal Science Advances the results of an analysis carried out on 35,000 women, of all origins, of age to have their periods or who have had them recently. It follows the many shares from 2021 of women who noticed unexpected bleeding after receiving a Covid-19 vaccine.

A more abundant flow in 42.1% of respondents

Effects on the menstrual cycle are widely confirmed. Initial findings from this analysis were that 42.1% of menstrual survey respondents reported heavier menstrual flow after receiving the COVID-19 vaccine. Some experienced it within the first seven days, others within 8-14 days after vaccination.

The analysis also shows that women who experienced a heavier flow than normal are women who have experienced pregnancy, those who have suffered from endometriosis, fibroids, or those who have experienced fever or fatigue as side effects. of the vaccine.

The analysis also shows that roughly the same proportion, ie 43.6% of the respondents, however, experienced no change in their flow.

Data to integrate into research?

For gynecologist Odile Bagot, questioned on the subject, this analysis only confirms what is also observed in France. “We cannot deny the effects recorded by the thousands with the CNAM, which are cycle disorders, such as a delay or absence of menstruation, abnormal bleeding or even postmenopausal women who notice new bleeding. Nevertheless, these are “transitional” disorders that have not resulted in serious consequences so far” she confirms.

As for the follow-up to be given to these studies, Dr. Bagot does not hide the difficulty that exists in drawing conclusions: “Even with these reports, however, it must be remembered that women are not Swiss clocks, that they experience menstrual disorders… which we compare here to vaccination. But which exist elsewhere. These reports are taken into account, of course, but it is difficult to make a strong correlation based on these statistics” she confides.

Covid also causes menstrual disorders

For Kathryn Clancy, professor of anthropology at the University of Illinois who led the research with Katharine Lee, professor of anthropology at Tulane University, the challenge is to integrate this parameter in future research: “We would like to see future vaccine testing protocols incorporate questions about menstruation that go beyond pregnancy screening”.

She adds : “We want to reiterate, however, that getting vaccinated is one of the best ways to avoid getting very sick with COVID, and we know that having COVID itself can lead to not only rule changes, but also hospitalization, long COVID and death.”