Background: Coronavirus disease (COVID-19), a highly infectious disease caused by the SARS-CoV-2 virus has taken the form of pandemic throughout the world and is a major public health problem. The effect of COVID-19 infection on menstruation cycle might be the adverse effect on the complex interplay of hormones that interact with immune, vascular and coagulation systems whose interaction can influence menstrual bleeding and severity of menstruation symptoms. However with the roll out of the COVID 19 vaccine among the younger age group, many complaints were received at the health centers regarding the change to their menstruation cycle. The present study was conducted to assess the effect of different types of Covid-19 vaccine on the menstruation cycle of the women. Material and Methods: It was a cross sectional prospective study in which data were collected by interviewing the women attending the MCH hospital and who are vaccinated by COVID 19 vaccination. The study sample contained 344 women. The sampling was done randomly by selecting every second eligible patient attending the out-patient department of Obs. and Gynaecology.The data were collected in the data collection form specially designed for this study. The data were entered and analyzed by using the SPSS, version 21.Descriptive statistics were presented using counts, proportions (%), mean ± standard deviation whenever appropriate. Descriptive statistics (e.g. number, percentage) and analytic statistics using Chi Square tests (?2) to test for the association and/or the difference between two categorical variables were applied. A p-value equal to or less than 0.05 was considered statistically significant. Results: A total of 314 subjects participated in study. The mean age of the participants was 29.56 years± Std. Dev. 8.29 years. Majority of the participants (67.5%) were married. Eighty six percent of the participants were immune by third dose while only 1% was immune by first dose and 7.6% by 2 doses of Covid-19 Vaccine. Almost forty six percent (45.9%) of the participants did not experience any change in their menstruation cycle after vaccination while 21.7% experienced irregular menstruation cycle and 15.9% experienced severe pain during the menstruation period. Minority of the participants complained about the heavy bleeding (7.6%), light bleeding and fewer days of period time (6.7%) and missed period without pregnancy (2.2%). Menstrual changes was significantly higher among the age group of 45-54 years of age as compared to 35-44 years , 25-34 years and 15-24 years of age group (90% vs. 51.95% vs.52.63%vs.52.69%, P=0.042). The menstrual cycle change was significantly more prevalent among the unmarried participants than married and divorced participants (60.42% vs. 50.94% vs.50%, P=0.045).Menstrual change was also significantly more among the participants with Type 2 diabetes as compared to those with no disease , hypertension and hypothyroidism (75% vs.50.57 vs.69.23 vs. 50%, P=0.043). The menstrual change was significantly more among the participants who were immune by first dose than those with second and third dose (80.0%vs.51.28% vs.53.70%, P=0.038). Conclusion: The present study has shown that there was evidence to support that following vaccination for COVID-19, menstrual disturbance do occur. Except Moderna vaccine the subjects in the present study had menstrual cycle irregularities regardless of the vaccine type. The presence of Type 2 Diabetes, hypertension, immunity by one dose, unmarried women and those with already irregular period were found to be the possible associated factors for the menstrual irregularities in our study. However, more specific studies such as case control are needed to validate the results of the present study.