Menstrual vulnerability to acute systemic stress: evidence from 884 women after COVID-19 infection.

BackgroundMenstrual function is sensitive to inflammatory, endocrine, and psychosocial stressors that may transiently disrupt the hypothalamic-pituitary-ovarian axis. Although menstrual disturbances have been reported during the coronavirus disease 2019 (COVID-19) pandemic, large real-world data from Asian populations remain limited. We aimed to describe menstrual changes reported after COVID-19 infection and to identify potential vulnerability factors.MethodsWe conducted a retrospective cross-sectional survey using an electronic questionnaire among reproductive-aged women who had experienced at least one menstrual cycle following laboratory-confirmed or self-tested COVID-19 infection between January and March 2023. Participants reported menstrual characteristics before and after infection. Multivariable logistic regression analyses were performed adjusting for age, age of menarche, abnormal uterine bleeding (AUB)-related disease, pre-existing menstrual irregularity, vaccination status, and fever.ResultsAmong 884 participants, 662 (74.9%) reported at least one menstrual change after infection. Alterations most commonly involved cycle length (421/884, 47.6%), menstrual flow (369/884, 41.7%), and duration (261/884, 29.5%). Women with pre-existing irregular cycles were more likely to report post-infection changes than those with regular cycles. In adjusted analyses, pre-existing menstrual irregularity remained independently associated with reporting menstrual changes (adjusted OR 1.51, 95% CI 1.12-2.03).ConclusionsMenstrual disturbances were frequently reported following COVID-19 infection and showed substantial interindividual variability. These findings suggest that menstrual function may be vulnerable to acute systemic stress. Because the study was cross-sectional and based on self-reported outcomes, the findings should be interpreted as associative rather than causal and may have been influenced by recall or selection bias. Prospective longitudinal studies are warranted.