Human papillomavirus (HPV), the virus that causes nearly all cervical cancers, can be reliably detected from menstrual blood collected on a sanitary pad, according to a new study. The findings add to growing interest in the diagnostic applications of a bodily fluid that researchers have historically overlooked.
The study, published in the BMJ, enrolled more than 3,000 women in China’s province of Hubei between September 2021 and January 2025. Participants collected menstrual blood using a small cotton strip affixed to a sanitary pad, and the researchers compared the results of HPV tests of that blood and of clinician-collected cervical samples from the same participants. Both methods were then measured against biopsy results to see how well they detected high-grade cervical lesions, which could consist of cancerous or precancerous cells. The menstrual blood method performed similarly to clinician-collected samples in detecting the types of HPV that are linked to cervical lesions.
“Menstrual blood [sample] collection using sanitary pads represents a promising innovation, offering a convenient and non-invasive alternative” or replacement to standard cervical cancer screening, the study authors write. Current screening typically involves a Pap smear, an often uncomfortable procedure in which a doctor or nurse scrapes a sample of cells from the cervix and examines them under a microscope for abnormalities.
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Trisha Amboree, an assistant professor at the Medical University of South Carolina, who studies cervical cancer screening, sees potential in the new method. “I believe that the more clinically effective and validated tools we have to reach a broader proportion of people who persistently remain underscreened, the better,” she says.
A 2022 pilot study found that 94 percent of participants preferred menstrual pad collection over clinician sampling. “The trade-offs of these different modalities can be really nuanced. I think it depends on the collection device, and it depends on individual preference,” Amboree says.
For cervical cancer screening specifically, some experts question whether menstrual collection offers advantages over vaginal swab self-collection, a method that the Food and Drug Administration approved in 2024 and that can be done in seconds at any point in the menstrual cycle except during menstruation. No large-scale study has directly compared menstrual blood collection with vaginal self-swabs—a gap the authors of the new paper acknowledge.
Rebecca Perkins, a professor of obstetrics and gynecology at the Tufts University School of Medicine, who serves on the American Cancer Society’s Guideline Development Group, is less enthusiastic about menstrual blood screening. “It would make it much harder for people to screen compared to a vaginal swab that can essentially be done almost any time on anybody,” she says. She notes that menstrual collection would only work “for a few days each month and only then if they were menstruating regularly”—excluding those who are postmenopausal, have irregular cycles or use certain kinds of birth control.
But Perkins sees broader promise for using menstrual blood for diagnostics. She suggests the technique might prove more useful for conditions that currently require invasive and uncomfortable testing—such as endometrial biopsies.