Background: Menstrual irregularities after COVID-19 vaccines have been widely reported. This study aims to evaluate Jordanian women's menstrual changes after receiving the COVID-19 vaccine.
Methods: This study is an analytical cross-sectional study conducted through an online self-administered questionnaire distributed through social media during June and July 2022. It involved 384 women between the ages of 20 and 35 who took the vaccine and did not suffer from gynaecological or medical conditions that affect menstruation, were not pregnant or lactating, were not utilising hormonal or intrauterine contraceptives, and had normal menstrual cycle length and regularity prior to vaccination.
Results: The results of this study showed a statistically significant increase in menstrual cycle length with a mean difference of 2 days (p=<0.001), but not in menstrual duration (p=0.824). 55.4% had their first period after vaccination on time. Eight participants reported new-onset intermenstrual bleeding. Additionally, 41.3% experienced changes in menstrual volume, and their first period came on time. Around one-third of women reported increased or new-onset dysmenorrhea. As for premenstrual symptoms, 30% reported increased or new-onset mood disturbances, 20.6% had changes in their sleeping patterns, 17% had increased headaches.
Conclusion: The study revealed that COVID-19 vaccination might cause changes in menstrual cycle length and new or increased menstruation problems in some women, including dysmenorrhea, premenstrual symptoms, and intermenstrual bleeding. These results emphasize the need for additional longitudinal research to understand the effect of COVID-19 vaccination on menstrual health and to provide support and education to women who experience menstrual abnormalities after vaccination.