A new study claims that the Covid vaccine would have (mild) effects on menstruation

Almost 39,000 responses collected from people between 18 and 80 years old: here it is the first major study on the effects of Covid-19 vaccines carried out by teams of researchers and anthropologists Kathryn Clancy and Katharine Lee, in the United States.

The goal: to allow the largest possible sample of people – consisting of cisgender women of menstruation, but also trans men, contraceptive women who prevent menstruation or postmenopausal women – list changes (or not) in their hormone cycle after vaccination.

From the start, the study is clear: it’s not about questioning the vaccine, but about having as much information as possible about its side effects. Thereby, ” In general, changes in menstrual bleeding are neither rare nor dangerous, but being interested in these experiences is necessary to build trust in medicine “, says the study.

More intense bleeding

Quoted on the site of Marie Claire, the study was published in the journal ScienceAdvance. It has been administered online to nearly 40,000 people worldwide, all fully vaccinated with one of the US approved vaccines, including Moderna, Pfizer, or Johnson & Johnson.

The answers prove it 42% People with regular menstrual periods surveyed reportedly experienced heavier bleeding after vaccination. 44% report no changes, e 14% report lighter rules.

Otherwise, in people who do not have or no longer have a menstrual period, 39% of hormone therapy respondents, as part of a gender transition, reported bleeding after one or both injections. This also applies to 71% of people taking long-acting contraceptives and 66% of postmenopausal women.

Some profiles most affected

The study highlights that some profiles are more at risk of presenting these changes. Therefore, people who have been diagnosed with reproductive diseases such as endometriosis, fibroids or polycystic ovary syndrome would be more at risk of seeing their bleeding become more profuse, as would those who used hormonal contraception and those who they had already been pregnant. .

According to Dr. Lee, quoted by the New York Times, this study is not adamant: there was no comparison with a control group of people who had not been vaccinated. It is also possible that people who observed changes in their cycle after vaccination were more likely to participate in the study.

However, the research team ensures this their results are perfectly consistent with research done on smaller cohorts, but with stricter controls.

On the French side, the National Agency for the Safety of Medicines has today put online a form for the declaration of menstrual disorders after vaccination and invites those affected to consult a health professional.

For the moment, without an explanation of this phenomenon (the causes of which can be multiple), the study is reassuring: in most cases, these disorders are not serious.

Photo credit: CDC / Unsplash