Objective: The study was conducted to know the impact of COVID-19 vaccination on menstrual cycle patterns, pre- and post-menstrual symptoms in women aged 18-45 years. Design & Setting: Multicentric observational study conducted in six institutes of national importance in different states of India over one year. Population: A total of 5709 female participants fulfilling inclusion criteria were enrolled. Methods: Data about impact of vaccines (COVISHIELD and COVAXIN) and prior COVID-19 infection on menstrual cycle and its associated symptoms were obtained using an online and offline survey. Main Outcome: COVID-19 vaccination with COVISHILED/COVAXIN resulted in menstrual cycle disturbances. Results: Of 5709 participants, 78.2% received COVISHIELD, 21.8% COVAXIN. Of all, 333(5.8%) developed post-vaccination menstrual disturbances with 32.7% frequent cycles, 63.7% prolonged cycles, and 3.6% inter-menstrual bleed. 301 participants, noticed changes in the amount of bleeding, with 50.2% excessive, 48.8% scanty, and 0.99% amenorrhea followed by heavy bleeding. Furthermore, the irregularities of menstrual cycle (p=0.011) and length (0.001) were significantly higher in the COVAXIN group (7.2%) as compared to COVISHIELD (5.3%). A total of 721 participants complained of newly developed/worsening pre- and post-menstrual symptoms. These symptoms were significantly higher in COVISHIELD group (p=0.031) with generalized weakness and body pains as main complaints (p=0.001). No significant difference was observed in COVID-19 infection incidence with these vaccines. When comparing menstrual abnormalities among those with COVID-19 infection, no significant associations were observed (p >0.05). Conclusions: COVISHILED and COVAXIN resulted in menstrual cycle disturbances and pre-and post-menstrual symptoms. The menstrual irregularities were significantly higher with COVAXIN vaccine.