Researchers say menstrual blood testing could provide a simple alternative to cervical screening.
A sanitary pad with a sample strip can detect human papillomavirus, the main cause of cervical cancer.
Scientists in China compared period blood tests with clinician-collected cervical samples.
The study involved more than 3,000 women aged 20 to 54.
Results appeared in BMJ.
Menstrual samples detected serious cervical cell changes with 94.7% sensitivity.
Clinician samples showed similar accuracy.
Both methods reliably ruled out disease when results were negative.
Researchers said the test could offer a non-invasive, home-based screening option.
Experts welcomed the findings but urged further trials.
Cancer Research UK said the approach could improve screening access.
Eve Appeal said choice in screening methods may increase participation.
