Although changes in menstrual cycle have not been noted as possible side effects after vaccination, there are women who have reported these to the Medicines and Healthcare products Regulatory Agency (MHRA) in the UK. So far, researchers have not noted a direct link between the two. To date, vaccination against COVID-19 is widespread. So far, according to the Centers for Disease Control and Prevention, possible side effects for the Moderna, AstraZeneca, Pfizer–BioNTech and Johnson & Johnson vaccines are pain, redness and swelling at the site where the vaccine was injected, as well as flu-like symptoms – fatigue, headache, muscle pain, chills, fever and nausea. Although menstrual irregularities are not noted as a side effect, more than 30,000 women have reported their presence. According to them, the changes that have occurred in the menstrual cycle are usually normalized by the next one. According to Dr. Victoria Mayle of Imperial College London in Great Britain, the observed changes in the menstrual cycle may also be the result of the body’s immune response to the vaccination, rather than a specific component of the vaccine. According to her, more in-depth research is needed on the subject. The study of the different effects of the vaccines against COVID-19 on the human body is needed to ensure a larger volume of reliable data. This information could reduce people’s worries and doubts. Another factor that affects the monthly cycle is stress. It can also cause its irregularity. A stress reaction can also occur in connection with the vaccination itself. Reasons for hesitancy among young women about vaccination include the possibility of affecting their reproductive systems. Many doctors, including Dr. Maile, reject such a possibility. Sources: https://www.medicalnewstoday.com/articles/do-covid-19-vaccines-affect-menstrual-cycles-expert-calls-for-investigation#Implications-on-womens-health https://www.bmj .com/content/374/bmj.n2211 https://www.cdc.gov/coronavirus/2019-ncov/vaccines/expect/after.html