Covid-19: a study confirms the risk of heavy menstrual bleeding linked to vaccination

Covid-19 : une étude confirme le risque de saignement menstruel abondant lié à la vaccination

A study whose results were published this Wednesday by the ANSM shows that the risk of heavy menstrual bleeding is increased by 20% between 1 to 3 months after the primary vaccination (two doses).

The risk of possible menstrual disorders has appeared on notices of heavy menstrual bleeding requiring hospital treatment, according to the National Medicines Safety Agency (ANSM) in a press release dated January 24.

A pharmaco-epidemiological study carried out by Epi-Phare (ANSM-Cnam scientific interest group) was carried out when cases of late periods, heavy bleeding, absence of periods were reported to the health authorities as part of the system reinforced surveillance of vaccines against Covid-19. Even before the results, "at European level, heavy menstrual bleeding was considered as an adverse effect of the Comirnaty and Spikevax mRNA vaccines by the EMA in October 2022 following the ;rsquo;evaluation of pharmacovigilance data, particularly those shared by the ANSM. These disorders were then added to the summaries of product characteristics (SPC) and the instructions for these two vaccines, specifies the ANSM.

8 women affected per 1 million women vaccinated

4,610 women aged 15 to 50 were included in the study. All were treated at the hospital between May 12, 2021 and August 31, 2022 for heavy menstrual bleeding. They had no history of hysterectomy or coagulation disorders. These cases were compared with a control group of 89,375 women with the same characteristics. 28.8% of women participating in the study had not been vaccinated, as were 28.7% of women in the control group.

Result: "the risk of heavy menstrual bleeding requiring hospital care was increased by 20% for women whose last dose received was a primary vaccination dose administered within the preceding 1 to 3 months. The risk was not observed 3 months after a primary vaccination dose nor after a booster dose. 8 cases of heavy bleeding are thus attributable to vaccination for 1 million vaccinated women, or 103 cases over the period studied. As a reminder, only women treated in hospital were included in the study.

"This study provides new arguments in favor of the existence of an increased risk of heavy menstrual bleeding following vaccination against COVID-19 by mRNA vaccine", concludes the study.