Long COVID Linked to Abnormal Uterine Bleeding and Menstrual Cycle Variations

Recent research from the Center for Reproductive Health at the University of Edinburgh highlights a significant association between long COVID and abnormal uterine bleeding among women in the UK. The study found that women experiencing long COVID reported increased menstrual volume, extended period durations, and more frequent intermenstrual bleeding. Notably, these changes occurred despite preserved ovarian function, suggesting other mechanisms at play.

Long COVID has been notably more prevalent in women, with emerging evidence pointing toward complex inflammatory and hormonal interactions affecting menstrual health. Previous reports during the pandemic indicated cycle irregularities post-infection, vaccination, or due to stress, with some transient menstrual disturbances observed. However, detailed insights into these menstrual disturbances and their underlying mechanisms remained limited.

In the recent study titled "The potential bidirectional relationship between long COVID and menstruation," published in Nature Communications, researchers combined data from a UK online survey, a prospective symptom-tracking cohort, and biological samples. The study included 12,187 participants, with a subset providing serum and endometrial tissue samples for detailed analysis.

Results demonstrated that women with long COVID experienced more heavy periods, longer cycles, and increased intermenstrual bleeding. Interestingly, symptom severity was found to peak during specific menstrual phases, especially the late secretory or menstrual phase. Serum analysis revealed elevated levels of 5α-dihydrotestosterone during long COVID episodes, while hormones such as estradiol, progesterone, and Anti-Müllerian hormone showed no significant group differences.

Tissue analysis uncovered fewer androgen receptor-positive cells in the endometrium during menstruation and proliferative phases, alongside increased serum tumor necrosis factor levels and immune cell infiltration within the menstrual endometrium. These findings suggest that persistent inflammation and altered androgen regulation could be responsible for the menstrual disturbances observed.

The study concludes that long COVID appears to disrupt menstrual health primarily through inflammatory responses and immune modulation, rather than direct ovarian failure. The authors advocate for targeted investigations into treatment options and emphasize the importance of considering menstrual cycles when developing biomarkers and therapeutic strategies for long COVID.

This research underscores the importance of recognizing menstrual health as part of the long COVID syndrome, highlighting the need for greater awareness and tailored interventions for affected women.

Source: https://medicalxpress.com/news/2025-09-covid-abnormal-uterine-phase-symptom.html