Millions of women were vaccinated in a few months to protect themselves against covid-19. Many of them reported changes in their menstruation shortly after receiving their dose, with irregular, heavier than usual, or less bleeding. Different pharmacovigilance systems in various countries, in charge of observing possible negative effects of drugs when they have already been approved, have registered these anomalies, which have also appeared in applications to follow the menstrual cycle and have been discussed on social networks or in gynecological consultations. . Although menstrual cycles vary naturally and these changes need not present a health concern, they may be a concern in a mass and accelerated vaccination campaign where adverse effects may not be well characterized. The European Medicines Agency recommended in October to include excessive menstrual bleeding as a possible side effect of unknown frequency in the information included with the vaccines.
To more accurately assess the risk of menstrual disturbances after receiving the SARS-CoV-2 vaccine, a team led by the Swedish Medical Products Agency has followed nearly three million women between December 2020 and February 2020. 2022. The results, which are published today in the magazine BMJ, indicate that there were no more medical contacts due to menstrual changes after receiving these vaccines in women with their period and only a slight increase was found in cases of bleeding in menopausal women with the third dose of the Pfizer and Moderna vaccines, something which was not observed with that of AstraZeneca. This slight association, according to the authors, is not enough to establish a causal relationship between the vaccines and bleeding.
Previously, studies have been carried out due to the concern that some vaccines produce changes in the menstrual cycle, as has happened with vaccines such as the papillomavirus, but no causal relationship has been found. Some works have collected some disorders, although the method makes the results inconclusive. A study published a year ago in the journal Science Advances, based on a survey of nearly 40,000 people, estimated that 42% of women with regular menstrual cycles reported heavier bleeding after inoculation with the covid vaccine. The researchers themselves recognized then that the findings show a trend, but they do not serve to say that the observed changes are caused by the vaccines and that the selection of the participants could inflate the results. “The people who participated were probably more likely to have experienced a menstrual change than the general population,” Katharine Lee, a professor at the Department of Anthropology at Tulanem University and co-author of the study, told EL PAÍS at the time. The researcher also commented that the imbalances that are usually reported and that have also been observed in association with covid are not long-lasting and usually disappear after a short time.
Santiago Palacios, spokesperson for the Spanish Society of Gynecology and Obstetrics, who did not participate in the work, points to the value of the result “due to the large number of vaccinated patients included” and highlights the authors’ consideration of the effects as irrelevant. registered secondaries. “As in the case of other vaccines, the authors talk about the emotional component of getting a vaccine, which can explain some changes in menstruation or bleeding,” he explains. Even so, Palacios considers that “it can be criticized that these changes are attributed to these emotional effects and not to some other reaction to the vaccine related to the immunological reaction.” As a general observation, the gynecologist, who in his clinical practice recognizes that menstrual disorders due to the vaccine “is something that patients raise with some frequency”, believes that when something unusual occurs, “such as being pregnant or having received a vaccine, you are more attentive to what happens to you and you can take into account as something relevant changes that under normal conditions would have been overlooked”.
Menstrual disorders were not included among the factors that were monitored during the initial trials of the vaccines, and additional follow-ups did not ask about these types of side effects either. Studies such as the one published today provide more information about the risk of suffering these types of effects and the way in which they can be interpreted. In that same line, Previous jobshave ruled out that SARS-CoV-2 vaccines cause fertility problems in men or women.
In recent years, the debate on coronavirus vaccines, much more intense than with any previous type of immunization, has had two consequences, according to a recent report Made for Unicef by the London School of Hygiene and Tropical Medicine. This study reported a reduction in immunization in almost all the countries included in the sample. In the Spanish case, vaccination continues at high levels, 88.6%, but it has been reduced by 8%. In addition to the lack of confidence, the distribution and production difficulties generated by the pandemic are behind the global reduction in the number of people vaccinated.
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