Covid vaccine: cases of menstrual disorders identified

In its update on the surveillance of vaccines against Covid-19 over the period from July 16 to 22, the National Agency for the Safety of Medicines and Health Products (ANSM) reports cases of menstrual disturbances after vaccination, with the Moderna vaccine but also that of Pfizer.

An immune system reaction

“The analysis of cases of menstrual disorders occurring after vaccination with Spikevax (36 cases since the start of the vaccination) led the monitoring committee to consider that this is a potential signal which also concerns Comirnaty, which has a similar profile. This potential signal will be brought to the European level”, Informs the Agency. For the Pfizer vaccine, 229 cases of menstrual disturbances have been reported. Concretely, some women have observed that their periods were more painful, heavier or delayed.

How to explain this possible cause and effect link? Interviewed by The Parisian, Professor Olivier Picone, obstetrician-gynecologist and member of the French National College of Gynecologists and Obstetricians (CNGOF), supports the hypothesis of an immune reaction: “The immune system is stimulated and will secrete proteins. But if they are secreted at too high a level, they will be able to disrupt the communication between the ovary and the hypothalamic-pituitary axis and therefore modify the menstrual cycle.“, he explains.

Are women taking contraception more concerned?

A recent pre-published study and relayed in the Dailymail indicates that the AstraZeneca, Pfizer and Moderna vaccines against Covid would rather seem to affect the menstrual cycles of women who are on contraception and not those who are not. Researchers at Imperial College London studied data from 1,273 women. As a result, among people on contraception, on average 42% reported having heavier periods than usual and 19% said they were lighter. By comparison, those without contraception were 32% to have heavier flow and 14% found it to be lighter. The researchers also point out that people with endometriosis were more likely to have their periods earlier than normal, while those with polycystic ovary syndrome were more likely to have periods later. The immunologist who led the study, Dr Victoria Male, said it was difficult to find a biological reason for this, and suggested that women who take the pill monitor their menstrual cycles more than others.

No long-term effect or serious risk

Last May, the BBC already reported the adverse effects of vaccination against Covid-19 on menstruation. Interviewed by the British media, Dr. Victoria Male, specialist in reproductive immunology, said for her part that the chemical signals emitted after vaccination could affect immune cells and modify the lining of the uterus, and thus cause bleeding or bring forward the date of your period.

In all cases, the experts want to be reassuring: menstrual disturbances after vaccination are temporary and not serious. No risk of infertility or miscarriage is to be feared.