Unexpected bleeding, ultra-painful or heavy periods… Some women have reported that after being vaccinated against Covid-19, they noticed menstrual problems. A subject rarely discussed … which nevertheless deserves attention.
Because a woman who hopes or fears a pregnancy risks to live badly these disturbances. Others, doubled over from painful periods, will go backwards to the third dose if it is generalized. And above all, fears around fertility have greatly fueled the doubts or convictions of some antivax. “If we had more data, maybe that could be reassuring,” suggests Marina kvaskoff, epidemiologist.
What do we know precisely?
According to’European Medicines Agency (EMA), possible effects on the menstrual cycle were not noted during clinical trials of the four Covid-19 vaccines authorized in Europe: Pfizer, Moderna, AstraZeneca and Jannsen. More recently,
the EMA pharmacovigilance risk assessment committee established on Oct. 6 that based on observational data, there is currently no evidence to suggest a causal link between Pfizer’s vaccine and menstrual disorders. In detail: 16,263 cases of cycle disorders have been reported, thus 6,118 serious, out of approximately 1.2 billion doses administered worldwide, men and women alike, as of August 31.
On the French side, 261 cases of menstrual disorders have been reported to theNational Medicines Safety Agency (ANSM) with Pfizer (the most used vaccine in France) on July 31, 2021, including 30 serious. And for Moderna: 238 cases of menstrual disorders, including 19 serious as of September 9, 2021.
On the last ANSM monitoring point, menstrual disorders are among the signals under surveillance … but come in 14th place out of 16. “The reported effects are very different (delayed or advanced menstruation) and relate to the intensity or duration of bleeding,” specifies the ANSM. These menstrual disorders, mostly non-serious (90% of reported cases), occurred for the majority of cases within 7 days of vaccination. The evolution is favorable in most cases within a few days. “
Among our British neighbors, the equivalent of the ANSM received 30,000 reports of similar adverse events after injection of AstraZeneca (adenovirus vaccine) and Pfizer (messenger RNA). “If there is a link, it is unlikely that it is the result of the composition, but of the immune reaction,” says Marina Kvaskoff.
A complicated subject to analyze
The concern is palpable, but the situation remains difficult to analyze. First, because not all women report these disturbances. “For the moment, we do not know the frequency of these effects on the rules and we have no study against placebo [un groupe témoin reçoit le vaccin tandis qu’un autre reçoit un simple placebo], to find out what is the share of causality and chance ”, nuance Olivier Picone, obstetrician-gynecologist at the Louis Mourier hospital (Colombes).
But also because “the menstrual cycle is very fragile, very sensitive to stress, infections, inflammation,” he continues. When you vaccinate, you induce an immune reaction and that can disrupt a cycle. For the HPV vaccine, we have already seen changes in the rules, although this is quite rare. The context of the vaccination can also cause psychosomatic reactions. “If there is mistrust of the vaccine, or opposition, the concern generated can influence the rules, adds Catherine Vidal, neurobiologist. It is also interesting that these effects have been observed
for HPV vaccine and Covid-19, two vaccines highly criticized in a context that is not serene. This is not the case for conventional vaccines that are well accepted socially. “
We should know more soon.An observational study on possible impacts on menstruation and menopause on 300 women, vaccinated with one of the four vaccines authorized in Europe, was indeed launched on October 21 by the
Università degli Studi dell’Insubria, in Italy.
“What is certain is that it has no impact on fertility: in two or three cycles, it is fine, reassures Olivier Picone. It’s unpleasant to have a disrupted cycle, but it doesn’t seem very common and that’s okay. “According to him, the fact that the first alerts emerged this summer does not indicate an abnormal delay:” the vaccination was generalized to young people in June and it was necessary to wait for several menstrual cycles.
A sign that the labs underestimate the specificities of women?
But is this studied enough? Research has long been criticized for its inability to take into account women and their specificities. “There were serious shortcomings at a certain time,” recalls Catherine Vidal, author of the report. “Taking sex and gender into account to provide better care: a public health issue” for the High Council for Equality. In the 1970s, after two scandals, those of distilbene and thalidomide, with children born with deformities and cancers, the United States Medicines Agency (FDA) recommended excluding women from clinical trials, ”de fear of including pregnant women for whom the consequences could be dramatic.
But things have changed dramatically since then. “According to the International Register of Clinical Trials (WHO / NIH), the participation of women rose from 35% in 1995 to 58% in 2018, underlines this report. However, for some pathologies, the persistence of an insufficient representation of women has been denounced, in particular in trials concerning heart failure, certain cancers, depression, pain and AIDS. This is not the case with anti-Covid vaccines: women represent 51% of patients included in Pfizer’s phase 3 clinical trials.
Should we go further?
“An important lesson is that the effects on the rules of a medical intervention should not be an afterthought in future research,” suggests British researcher Victoria Male, specialist in reproductive immunology, in a letter published by the British Medical Journal. Clinical trials provide the ideal setting to differentiate menstrual changes caused by interventions from menstrual changes that occur anyway, but participants are unlikely to report period changes unless specifically requested. “For this researcher, therefore,” information on menstrual cycles and other vaginal bleeding should be actively sought in future clinical trials. “
This would not have been the case with vaccines against Covid-19. Contacted by 20 minutes, Pfizer specifies that “during phase 3 clinical trials, the laboratory does not guide participants, who are asked to report all possible side effects. There is therefore no particular focus on the rules. (In contrast) menstrual disturbances were not reported by participants directly. “Pfizer specifies that” this question is being studied in real life [a posteriori] “. Moderna, also contacted by 20 minutes, had not answered our questions at the time of this publication.
Olivier Picone, however, wants to be confident for the future: “now that it is common knowledge, it is certain that the effect on menstrual cycles will appear in the questions on side effects for future vaccine trials. Labs have every interest in playing with transparency. “