Menstrual changes after vaccination against covid-19

Common side effects of covid-19 vaccination listed by the UK Medicines and Health Products Regulatory Agency (MHRA) include arm pain, fever, fatigue and myalgia. people working in reproductive health are increasingly approached by people who have experienced these events shortly after vaccination. As of September 2, 2021, more than 30,000 reports of these events had been submitted to the MHRA Yellow Card Surveillance Scheme for Adverse Drug Reactions to All Covid-19 Vaccines Currently Offered.1

Most people who report a change in their period after vaccination find that it returns to normal the next cycle and, importantly, there is no evidence that covid-19 vaccination negatively affects fertility. In clinical trials, unwanted pregnancies occurred at similar rates in vaccinated and unvaccinated groups.2 In assisted reproduction clinics, fertility measures and pregnancy rates are similar in vaccinated and unvaccinated patients.

MHRA states that the evaluation of the yellow card reports does not support any link between changes in menstrual periods and covid-19 vaccines, as the number of reports is low in relation to both the number of people vaccinated and the prevalence of menstrual disorders in general. the way the yellow card data is collected makes it difficult to draw firm conclusions. Better-equipped approaches are needed to compare menstrual variation rates in vaccinated and unvaccinated populations, and U.S. National Institutes of Health have made $ 1.67 million (£ 1.2 million; 1) available. 4 million euros) to encourage this important research.

Menstrual changes have been reported after covid-19 vaccines vectored by mRNA and adenovirus, 1 suggesting that, if there is a connection, it is likely to be the result of the immune response to vaccination rather than a vaccine component. specific. Human papillomavirus (HPV) vaccination has also been associated with menstrual changes.9 In fact, the menstrual cycle can be affected by immune activation in response to various stimuli, including viral infection: in A study on menstruating women, about a quarter of people infected with SARS-CoV-2 experienced menstrual disorder

Biologically plausible mechanisms linking immune stimulation to menstrual changes include immunological influences on hormones that drive the menstrual cycle11 or effects mediated by immune cells in the lining of the uterus, which are involved in ‘accumulation and cyclic degradation of this tissue. a possible association between covid-19 vaccines and menstrual changes may also help to understand the mechanism.

Although the changes reported in the menstrual cycle after vaccination are short-lived, solid research on this possible adverse reaction remains critical to the overall success of the vaccination program. Vaccination of vaccines among young women is largely due to false claims that covid-19 vaccines could harm their chances of pregnancy in the future13. If a link is confirmed between vaccination and menstrual changes, this information will allow people to plan for potentially altered cycles. Clear and reliable information is particularly important for those who are confident in being able to predict their menstrual cycles to achieve or avoid pregnancy.

We are still waiting for definitive evidence, but in the meantime, how should doctors who have experienced these effects advise? Initially, they should be encouraged to report any changes in periods or unexpected vaginal bleeding in the MHRA’s yellow card scheme. This will provide more complete data to facilitate the investigation of any link and indicate to patients that their concerns about vaccine safety are taken seriously, building trust. In terms of management, the Royal College of Obstetricians and Gynecologists and the MHRA recommend that anyone reporting a change in periods that persist for several cycles, or new vaginal bleeding after menopause, should be managed accordingly. the usual clinical guidelines for these conditions.

An important lesson is that the effects of medical interventions on menstruation should not be a later reflection in future research. Clinical trials provide the ideal framework for differentiating menstrual changes caused by interventions from those that occur anyway, but participants are unlikely to report changes in periods unless specifically asked. Information on menstrual cycles and other vaginal bleeding should be actively sought in future clinical trials, including trials with covid-19 vaccines.