Researchers say menstrual blood testing could offer a simple, non-invasive alternative to cervical screening.
A sanitary pad fitted with a sample strip can detect human papillomavirus, which causes most cervical cancers.
Scientists in China compared menstrual blood samples with clinician-collected cervical samples.
The study involved more than 3,000 women with regular menstrual cycles.
Results published in BMJ showed high accuracy for detecting serious cervical abnormalities.
The pad-based test detected disease at rates similar to clinician sampling.
Researchers said the method could improve screening access for women who avoid clinic appointments.
Cancer Research UK called the approach encouraging but said further trials were needed.
Eve Appeal welcomed the findings as a potential life-saving option.
Experts stressed the test may not suit everyone and remains in early research stages.
