In the United Kingdom, more than 30,000 women after the Covid vaccination have submitted reports of changes in the menstrual cycle to the Mhra drug agency surveillance program for adverse drug reactions (as of 2 September 2021). The reports cover all vaccines currently offered in the country. And for reproductive immunology professor Victoria Male, “a link is plausible and should be studied.”
This is the message that the expert of the Department of Metabolism, Digestion and Reproduction of the Imperial College London – Chelsea and Westminster Hospital Campus in London, launches in an editorial published in the scientific journal ‘BMJ’ in these days. Common vaccination side effects listed by the Drug Agency, he explains, include pain in the arm where the injection is given, fever, fatigue, and myalgia. Changes to menstruation (such as interruptions of the cycle) eland unexpected vaginal bleeding are not listed, the specialist points out. But general practitioners and experts who work in the field of reproductive health “they are increasingly approached by people who have experienced these events shortly after “the injection.”.
Most women who report a change in their cycle find that anyway everything returns to normal with the next cycle “and, above all – points out the expert – there is no evidence that vaccination against Covid-19 negatively affects fertility. In clinical trials, “in fact,” unwanted pregnancies occurred at similar rates in vaccinated and unvaccinated groups. “And” in assisted reproduction clinics, fertility measures and pregnancy rates are similar “in vaccinated and unvaccinated women.
The UK regulator says the assessment of reports does not support a link between changes in menstrual cycles and Covid vaccines, as the number is low compared to both vaccinated people and the prevalence of menstrual disorders in general. “However – observes Male – the way in which data is collected” with these reports “makes it difficult to draw firm conclusions. Better equipped approaches are needed to compare the rates of menstrual variation in vaccinated versus unvaccinated populations and the National Institutes of US Health has made $ 1.67 million (€ 1.4 million) available to encourage this important research. “
Menstrual changes have been reported after both mRna and adenoviral vector vaccines, “suggesting that, if a connection exists, it is likely to be the result of the immune response to vaccination, rather than a specific component of the vaccine.” Human papillomavirus (HPV) vaccination has also been associated with menstrual changes.
In fact, the scientist reasoned, “the menstrual cycle can be affected by immune activation in response to various stimuli, including viral infection: In a study of menstruating women, about a quarter of Sars-CoV-2 infected women had a break in menstruation. Biologically plausible mechanisms linking immune stimulation to these changes include immunological influences on hormones that drive the menstrual cycle or effects mediated by immune cells in the lining of the uterus, which are involved in the cyclic accumulation and rupture of this tissue. “Moral : research can help understand the mechanism.
“Although the reported cycle changes are short-lived – continues Male – solid research on this possible adverse reaction remains critical to the overall success of the vaccination program. Vaccination hesitation among young women is largely driven by false claims. that Covid vaccines could harm their chances of future pregnancy. Failing to thoroughly investigate reports on post-injection menstrual changes risks fueling these fears. If a link between vaccination and altered cycle is confirmed, this information is particularly important for those who rely on the ability to predict their menstrual cycles to achieve or avoid pregnancy “.
While definitive evidence is awaited, what should doctors recommend to those who have experienced these changes? Meanwhile, according to the expert “you should be encouraged to report them” to the supervisory systems. Because this “will provide more comprehensive data to facilitate research and show patients that their concerns are taken seriously, building trust.”
An important lesson, concludes the specialist, is that the effects on menstruation of medical interventions should not be a secondary thought in future research. “Clinical trials provide the ideal environment in which to” address the issue, but “participants are unlikely to report changes in the cycle unless specifically requested. This information should be actively sought in future clinical trials, including Covid vaccine studies.” .