Women affected by menstrual disorders that appeared after vaccination against Covid-19 are invited to declare them, the Medicines Agency (ANSM) said on Tuesday July 19, in a context of uncertainty about a direct link between vaccines and these troubles.
Menstrual disorders declared after vaccination with an mRNA vaccine, namely those of Pfizer/BioNTech and Moderna, have been the subject of careful monitoring at national and European level since their detection, recalls the agency. Multiple testimonies evoke the appearance of disorders after an anti-Covid vaccination, but the health authorities have not yet established a cause and effect link.
Disorders that appeared after vaccination
As of April 28, the regional pharmacovigilance centers have analyzed 9381 declarations of cycle disorders reported with the Pfizer vaccine, and 1557 with the Moderna vaccine, reports the ANSM. The majority of these declarations were made by the patients directly, specifies the agency. By this date, 58 million injections had been made in women with the Pfizer vaccine, and 12 million with that of Moderna.
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The Medicines Agency invites women to declare menstrual disorders that have appeared after vaccination on the portal of the Ministry of Health (signalement.social-sante.gouv.fr), providing “the most detailed information possible in the declaration form“. It has posted a declaration assistance guide online as well as tutorials for patients and healthcare professionals. The elements collected must allow “the regional pharmacovigilance centers to conduct their assessment of reported cases as efficiently as possible“, she says.
Reactogenicity that influences hormones
At this stage, adverse events most often remain “not serious” and generally manifest themselves in two ways: by abnormal bleeding (metrorrhagia, menorrhagia), and by delayed menstruation or amenorrhea, underlines the agency. To date, the available data do not allow us to describe the mechanism of occurrence of these menstrual cycle disorders, she adds.
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However, she cites several hypotheses such as reactogenicity (fever, headache, nausea, etc.) caused by vaccination which could, as during an infection, influence the hormones involved in the menstrual cycle. Or even a significant stress, caused by the act of vaccination, likely to disturb the hypothalamic-pituitary-ovarian axis which regulates the smooth running of the menstrual cycle.
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