Does the coronavirus vaccine actually disrupt women’s menstrual cycles? According to a recent study, the latter could be extended by less than a day because of the anti-Covid serum. This effect linked to the release of cytokines would be slight and “temporary”.
- Since the start of the vaccination campaign, 3,870 cases of menstrual disorders have been observed after vaccination with Pfizer and 562 cases after an injection of Moderna.
- Vaccines against Covid-19 would have a slight impact on the menstrual cycle. They would lengthen it by less than a day but would not disturb the duration of the period.
Postponed menstruation, absence of periods, heavier bleeding… Since the start of the vaccination campaign, several women have noticed suffering from menstrual disorders after having received the vaccine against Covid-19. A question has therefore arisen for several months: does the serum against the coronavirus modify their menstrual cycle? A study, published in review Obstetrics & Gynecology on January 5, provided some answers. In the latter, American researchers indicated that vaccination could slightly disrupt the menstrual cycle of women.
The menstrual cycle lengthened by less than a day after vaccination
For the purposes of the work, the scientists examined data including 3,959 women aged 18 to 45 with regular cycles of a length considered normal (between 24 and 38 days). They did not use contraception. A total of 2,403 women were vaccinated (55% with Pfizer, 35% with Moderna and 7% with Janssen). The rest of the participants had not benefited from the formula against the coronavirus. The researchers studied the length of the menstrual cycle of vaccinated women three months before vaccination and three months after the injection. They also analyzed the six consecutive cycles of the unvaccinated participants.
A “temporary” effect
The verdict is in. According to the results, the Covid-19 vaccine was associated with less than a day’s change in cycle length after an injection compared to cycles before vaccination. As for the non-vaccinated people, they did not see any significant change. This slight change in cycle length, not menstrual length, would be a “non-serious” effect and “temporary”.
“We find no clinically significant change in menstrual cycle length associated with vaccination against Covid-19,” the scientists said. According to Alison Edelman, study author and professor of obstetrics and gynecology at Oregon Health & Science University, the International Federation of Gynecology and Obstetrics classifies any change lasting less than eight days as normal. These results “are very reassuring”she added to AFP.
How to explain this slight effect on the menstrual cycle?
“We know that the immune and reproductive systems are interconnected,” explained Alison Edelman. The strong immune response created by the vaccine affects the hypothalamic pituitary-ovarian axis, which is described by the professor as “the communication highway between the brain, ovaries and uterus”. This axis helps regulate the menstrual cycle. With vaccination, “you release proteins called cytokines, which we know from other diseases can throw this body clock (namely the hypothalamic pituitary-ovarian axis) out of whack,” she elaborated.
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