Exploring Menstrual Disorders in Two Different Areas, Hamedan and Zahedan in Iran, after the Injection of the COVID-19 Vaccine

Background and Purpose: After the injection of the COVID-19 vaccinations, many women around the world have reported abnormalities in their menstrual periods. Hence, the objective of our study was to compare the prevalence of menstrual abnormalities after the COVID-19 vaccine among females residing within two regions (Hamedan and Zahedan) that are different in the length of sunlight in Iran. Method: The research (cross-sectional study) utilized a questionnaire to evaluate the menstrual status following COVID-19 vaccination. Based on the determined sample size, 170 women were selected, with 85 from Hamadan and 85 from Zahedan (both situated in Iran). Checklists were distributed among women above the age of menarche in both regions who had been vaccinated, were not pregnant or lactating, and did not have a history of primary ovarian insufficiency, hypothalamic menopause, or hysterectomy. The demographic and clinical characteristics were assessed through the questionnaire, which consisted of three parts: demographics, menstrual disorders after vaccination, and length/repetition/quantity of menstruation disorders. Data analyzed using SPSS software at descriptive and inferential levels included frequency, percentage, Chi-Square, and Fisher exact tests, which were used for comparison. Results: A total of 170 females were included in our study; 85 females were from the Hamedan region, and 85 females were from the Zahedan region. About 57.6% of participants reported menstrual symptoms post-vaccination in the Hamedan region, and around 54.1% of women experienced these disorders in the Zahedan region (P-value 0.643). The frequency of people in the study who had disorders in length was higher in the Hamedan region (P-value 0.208). Also, disorders in the intensity and recurrence of their menstruation were higher in the Hamedan region than in the Zahedan region (P-value 0.054). Conclusion: This research has demonstrated a potential correlation between the intensity of menstrual disorders experienced by women following the administration of the COVID-19 vaccine and the duration of sun exposure, which impacts the level of vitamin D in the body. Hence, it is crucial to comprehend and substantiate this association as it holds significant value for the well-being of women and, subsequently, the health of future generations.