Long COVID Linked to Abnormal Uterine Bleeding in Women: Study
UK: A U.K. study found that long COVID is associated with abnormal uterine bleeding but not with impaired ovarian function. Researchers noted a potential bidirectional relationship between long COVID and menstruation, while also highlighting that both COVID infection and vaccination have been linked to menstrual disruptions.
The research, published in Nature Communications by Jacqueline A. Maybin of the Centre for Reproductive Health, University of Edinburgh, and colleagues, explored how SARS-CoV-2 infection might influence menstrual health and how the menstrual cycle could, in turn, affect the course of long COVID. The team analyzed data from thousands of women to clarify whether infection or persistent post-COVID symptoms alter menstrual patterns or ovarian activity.
Using a large U.K. population cohort, investigators compared women who never had COVID-19 (9,423 participants) with those who recovered from acute infection (1,716) and those living with long COVID (1,048). Women with long COVID were significantly more likely to report abnormal uterine bleeding, including heavier or longer periods and spotting between cycles. In contrast, participants who recovered from acute infection reported little to no menstrual disruption, underscoring that persistent symptoms, rather than the initial illness, were linked to these changes.
To understand how symptom intensity varies across the menstrual cycle, the researchers followed 54 women with long COVID. They found that fatigue, pain, and other long COVID complaints were most severe during the perimenstrual and proliferative phases, the time surrounding menstruation and early cycle development. This pattern suggests hormonal or immune changes tied to the menstrual cycle may amplify long COVID symptoms.
The study led to the following findings:
- Blood and endometrial samples from women with long COVID showed elevated levels of 5α-dihydrotestosterone and reduced endometrial androgen receptors compared with those of women without COVID-19.
- Other ovarian hormones remained stable, indicating that ovarian function was preserved despite these hormonal changes.
- Immune analysis revealed heightened inflammatory signals, including increased cytokines and clusters of immune cells in menstrual tissue.
- The findings point to an inflammatory mechanism underlying abnormal uterine bleeding and symptom flare-ups in long COVID.
The authors propose that the combination of increased androgens and a heightened endometrial inflammatory response could drive abnormal bleeding and worsen long COVID symptoms around menstruation. They emphasize that while ovarian function appears intact, the endometrium—the uterine lining—shows signs of immune dysregulation.
These findings support a two-way interaction: long COVID can disrupt menstrual patterns, and phases of the menstrual cycle may intensify long COVID manifestations. The researchers call for further studies to develop treatments targeting abnormal uterine bleeding in long COVID, incorporate menstrual-cycle timing into biomarker research, and prioritize therapies tailored to women experiencing persistent post-COVID symptoms.
"By revealing how long COVID and menstruation may influence one another, the study highlights the importance of considering female reproductive health in understanding and managing the long-term effects of COVID-19," the authors concluded.
Reference:
Maybin, J. A., Walker, C., Watters, M., Homer, N. Z., Simpson, J. P., Robb, C., Gibson, D. A., Jeanjean, L., Critchley, H. O., Kountourides, G., Olszewska, Z., & Alvergne, A. (2025). The potential bidirectional relationship between long COVID and menstruation. Nature Communications, 16(1), 1-19. https://doi.org/10.1038/s41467-025-62965-7
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