Long COVID Mice Show Fibroid-Like Uterine Lesions
A University of Miami study found uterine tissue changes one year after infection in a mouse model of long COVID.
Updated on Nov. 7, 2026 in COVID-19
Researchers found fibroid-like uterine lesions and inflammation one year after infection in mice modeling long COVID. The study was published in Microorganisms.
Why it matters
The findings suggest long COVID may affect the female reproductive system, an area that has received limited study. Researchers say the mouse model could help investigate how other viruses affect reproductive health.
Nearly all infected mice showed unusual changes to uterine epithelial cells, compared with roughly 1-3% of control mice. Whether these lesions appear in humans has not been established.
The players
University of Miami Miller School of Medicine
A medical school in Miami whose researchers led the study on long COVID and uterine lesions.
The details
Researchers experimentally infected mice with murine hepatitis virus-1, an analog of SARS-CoV-2, to model long COVID. One year later, the team examined uterine tissue and found inflammation and fibroid-like lining growth, with high levels of fibroid-associated proteins; two of these proteins were also detected in blood serum.
Timeline
One year after infection: uterine tissue examined and lesions observed.
Researchers are repeating the study to examine the uterus days and months after infection.
Health Landscape
Earlier long COVID research has focused largely on the lungs, heart, and nervous system, leaving reproductive effects understudied. This mouse work extends that research toward the female reproductive tract, a area that has received little attention in long COVID studies.
The findings do not yet change treatment for people with long COVID. Anyone experiencing unusual menstrual changes after infection should discuss them with a clinician, since the mouse results have not been confirmed in humans.
The takeaway
Long COVID research is beginning to examine effects beyond the lungs and heart, including the reproductive system. Readers should watch for human studies before drawing conclusions about fertility or uterine health.
What happens next
Researchers are repeating the study to test the mouse uterus at days and months after infection and plan transcriptome sequencing to identify genes driving fibroid growth.
Further reading
For more on the broader pandemic, see COVID-19 coverage.
Source note: This article includes information reported by PNAS.
