Background: In 2020, global spread of the coronavirus pandemic began. Subsequently, various companies compete to develop numerous vaccines which have shown varying side effects. Assessing menstrual abnormalities post covid -19 vaccination can help understand whether the vaccine might influence menstrual health. We aim to assess the menstrual abnormalities after the COVID-19 vaccination among females working at Zagazig University.

Methods: A cross-sectional study was conducted in the medical and administrative sectors at Zagazig University. The study included 346 females in the childbearing period from March to September 2023. A semi-structured questionnaire was divided into three sections: demographics, COVID-19 vaccination data, and data about the menstrual cycle.

Results: The mean age of participants was 36.76 years. Of them, 67.9% worked in the medical field, and 92.5% received the COVID-19 vaccination. About 43% of vaccinated women subjectively identified changes in their menstrual cycle. There is a statistically significant relationship between change in menstruation after COVID-19 vaccination and the presence of minor adverse effects and the number of doses. Receiving two doses of vaccines non-significantly increased the risk of menstrual changes by 1.478 folds, while receiving three doses and experiencing minor adverse effects post-vaccination significantly independently increased the risk by 2.531 and 1.625 folds, respectively.

Conclusion: About forty percent of vaccinated females reported menstrual changes post-vaccination. COVID-19 vaccination had effect on menstrual health which is linked to vaccination doses and immunologic response to vaccine. We recommend implementing screening programs in family health centers, and to limit number of doses to least effective ones.