Does the Covid-19 vaccine have an adverse effect on menstrual cycles ?

According to a study led by CNRS researcher Alexandra Alvergne1 , the Covid-19 vaccine does not cause advserse menstrual changes. This conclusion was reached by a Franco-British team after analysing the results of a 2021 UK survey that questioned 12,000 menstruating women of all ages (vaccinated and unvaccinated against Covid-19), with or without children, from all geographical regions. From this sample, only one in five women reported menstrual problems after having the Covid-19 vaccine. Further investigations noted that the risk of menstrual changes was higher in women who smoked, had previously been ill with Covid-19, or were not using contraceptives containing estradiol (e.g. the combined contraceptive pill). According to the team’s scientific analysis, vaccination alone does not lead to an increase in abnormal menstrual cycle parameters. These results, recently published in iScience, are reassuring – vaccination against Covid-19 does not cause worrying menstrual changes. In fact, for the majority of women, the most common responses were normal, regular cycles of up to 70%.

• 1l’Institut des sciences de l'évolution de Montpellier (CNRS/Université de Montpellier/IRD)