Factors affecting menstrual cycle changes following COVID-19 vaccination in Korean women of reproductive age: an...

This study aimed to examine the impact of coronavirus disease 2019 (COVID-19) vaccination on menstrual cycle changes among Korean women of reproductive age.

This exploratory correlational study used data from an online, self-administered questionnaire obtained from the Korea Social Science Data Center database. The survey assessed menstrual cycle changes following COVID-19 vaccination among Korean women of reproductive age (15-49 years) who were menstruating regularly and had a history of COVID-19 vaccination. Data were collected between February and March 2023. A total of 227 participants who completed the online questionnaire were included in the analysis.

The risk of menstrual cycle changes was higher among older women (reference group: 40-49 years; 15-19 years: odds ratio [OR], 0.25 [p=.006]; 30-39 years: OR, 0.03 [p=.030]), women with obesity (reference group: body mass index [BMI] >23 kg/m2; BMI <18.5 kg/m2: OR, 0.03 [p=.030]; BMI 18.5-22.9: OR, 0.002 [p=.002]), and unmarried women (OR, 3.02). Increased risk was also observed among participants with a history of COVID-19 infection (OR, 3.46; p=.015), those who received the second or lower dose of the vaccine, and those reporting excessive menstrual flow (OR, 2.07; p=.015), intermenstrual symptoms (OR, 2.72; p=.037), or irregular menstruation (OR; 5.37, p<.001).

Menstrual cycle changes following COVID-19 vaccination appear to be influenced by multiple factors, particularly the interaction between a history of irregular menstruation and environmental conditions. Further longitudinal studies and tailored management strategies for specific subgroups, including unmarried and obese women, are needed to support women's health and quality of life.