Effect of COVID-19 Vaccination on the Menstrual Cycle Among Women in Dubai.

Introduction The impact of COVID-19 vaccination on menstrual cycle regularity has raised public health concerns, particularly regarding vaccine hesitancy. Studies report mixed findings, ranging from minor, transient changes to more significant menstrual alterations, highlighting the need for post-vaccination monitoring. This retrospective observational study aimed to describe self-reported menstrual changes before and after COVID-19 vaccination among women aged 18-40 years in Dubai, UAE, including changes in menstrual flow, cycle interval, and associated symptoms, and to compare findings between recipients of the Pfizer and Sinopharm vaccines. Materials and methods This multicenter, retrospective observational study included 398 women who received either the Sinopharm or Pfizer vaccine over a six-month period and were subsequently asked about the regularity of their menstrual cycles before and after vaccination. Results Among 398 adult women (mean age 28.7 ± 5.0 years) vaccinated with Pfizer (73.1%) or Sinopharm (26.9%), 91.7% had regular menstrual cycles before vaccination. Post-vaccination, 78% of those with regular cycles maintained regularity, while 14% developed irregularities, more frequently among Pfizer recipients and women on hormonal therapy. Reported menstrual changes included prolonged cycles (5%), dysmenorrhea (3.8%), heavier bleeding (2.8%), shortened cycles (2.5%), spotting (1.3%), and amenorrhea (0.8%). Conclusions Our study demonstrated that some participants reported menstrual irregularities following receipt of either the Pfizer or Sinopharm vaccines. However, due to the retrospective observational design and limited follow-up period, the findings demonstrate only a temporal association, and it remains unclear whether these reported changes were temporary or directly related to vaccination.