Menstrual Blood Test Detects Cancer as Well as Pap Smears

Cervical cancer screening might be about to get a whole lot easier for millions of women worldwide.

A major study published in the BMJ shows that menstrual blood collected on a small cotton strip attached to a sanitary pad can detect human papillomavirus (HPV) just as reliably as samples collected by a doctor during a standard exam. HPV causes nearly all cervical cancers, making early detection critical for prevention.

Researchers in China's Hubei province enrolled more than 3,000 women between September 2021 and January 2025. Each participant collected menstrual blood at home using the simple cotton strip method, then received a traditional cervical screening from a clinician.

When both methods were compared against biopsy results, the menstrual blood test performed just as well at detecting high-grade cervical lesions. These lesions can be cancerous or precancerous cells that need treatment.

The findings matter because current screening involves a Pap smear, where a doctor or nurse scrapes cells from the cervix. The procedure is often uncomfortable and keeps many women from getting screened regularly. A 2022 pilot study found that 94 percent of participants preferred the menstrual pad collection method over clinician sampling.

"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," says Trisha Amboree, an assistant professor at the Medical University of South Carolina who studies cervical cancer screening.

The Ripple Effect

This breakthrough could extend far beyond cervical cancer screening. Medical researchers have historically overlooked menstrual blood as a diagnostic tool, but that's changing fast.

Rebecca Perkins, a professor of obstetrics and gynecology at Tufts University School of Medicine, sees even bigger promise. She suggests the technique might prove especially useful for conditions that currently require invasive and uncomfortable testing, like endometrial biopsies.

The method does have limitations. It only works for a few days each month and requires regular menstruation, excluding postmenopausal women and those with irregular cycles or certain birth control methods. The FDA approved vaginal self-swabs for HPV testing in 2024, which can be done anytime except during menstruation and takes just seconds.

Still, having more options means more women can choose what works best for their bodies and schedules. No large-scale study has yet compared menstrual blood collection directly with vaginal self-swabs, but researchers acknowledge this gap needs filling.

The study authors call menstrual blood collection "a promising innovation, offering a convenient and non-invasive alternative" to standard screening. For women who've been putting off screening because of discomfort or inconvenience, this could be the breakthrough that finally makes prevention accessible.