Impact of COVID-19 Vaccination on Menstrual Cycle: A Cross-Sectional Study From Karachi, Pakistan.

Background The coronavirus disease 2019 (COVID-19) disease triggered a worldwide health catastrophe. To deal with this deadly situation multiple vaccines were developed and a mass immunization program started globally. However, vaccine hesitancy was seen, especially among women of reproductive age, having concerns that the vaccine might affect their menstrual cycle. This study investigated the link between COVID-19 vaccination and menstrual abnormalities. It is essential for us to understand the effects of vaccines on menstruation as menstrual distress can have effects on everyday life, and mental and reproductive health. Methods A cross-sectional study was performed using self-administered online forms to collect data from all over Karachi. The sample included 384 females aged 18 years and above. The data were collected from November 2021 to February 2022. Results Majority of the participants were aged 21 years and had a normal body mass index (BMI). Most were moderately stressed (n=245) with 146 reporting menstrual changes post-vaccination. The difference between the post-vaccine menstruation affected (n=146) and the unaffected cohort (n=238) was significant. Other factors which likely contributed to the post-vaccine menstrual changes included Perceived Stress Scale (PSS) score, strenuous physical activity, and the pre-vaccine menstrual flow. Conclusions Among the women vaccinated for COVID-19, strenuous physical activity and high perceived stress levels affected the menstrual cycle. There is no denying that existing data are inadequate, which is one of the grounds for vaccination apprehension, particularly among menstruating women. To minimize this hesitation, the spread of disinformation about the vaccine's influence on the menstrual cycle must be avoided. In future research and clinical trials, menstruation-related side effects should also be investigated when developing vaccines.