Sometimes, medtech innovation can be found in the unlikeliest of places.

Consider, for example, the technology in progress at ETH Zurich, where researchers have developed a device for spotting biomarkers directly in menstrual blood. The electronic-free sensor technology does not rely on a laboratory and could help facilitate early disease detection.

MenstruAI renders health data from menstruation systematically usable for the first time, according to researchers. The application is simple: users wear the sanitary towel with the integrated non-electronic sensor, take a photo of the used towel with a smartphone, and use an app to analyze it.

Menstrual Blood as an Information Source

More than 1.8 billion individuals menstruate, yet menstrual blood hardly plays any role in medicine. “This reflects a systemic lack of interest in women’s health,” stated Lucas Dosnon, first author and doctoral student in the group of Inge Herrmann, a professor at the University of Zurich, Balgrist University Hos-pital, Empa, and accredited at the Department of Mechanical and Process Engineering at ETH Zurich. “To date, menstrual blood has been regarded as waste. We are showing that it is a valuable source of information.”

Menstrual blood contains hundreds of proteins, and many of them can be correlated to their concentration in venous blood. Numerous diseases, including tumors such as ovarian cancer or endometriosis, lead to the presence of certain proteins in blood, which can serve as biomarkers for disease detection.

ETH researchers used three biomarkers as a starting point for MenstruAI. They currently record the C-reactive protein (CRP) as a general inflammation marker; the tumor marker CEA, typically elevated in various cancers; and CA-125, a protein that often is elevated in endometriosis and ovarian cancer. Many other protein-based biomarkers are being currently investigated and will be included in MenstruAI’s detection technology.

Same Functionality as a COVID-19 Test

MenstruAI uses a paper-based rapid test strip, a principle that is also familiar from COVID-19 self-tests but these strips analyze blood rather than saliva. When the menstrual blood biomarker makes contact with a specific antibody on the test strip, a colored indicator appears. The indicator’s color intensity varies depending on the concentration of the corresponding protein. The higher the concentration, the darker the color. The test area is embedded in a small flexible silicone chamber, which can be combined with a commercially available sanitary towel. Only a controlled volume of blood reaches the sensor without smearing or falsifying the test.

The results can be read with the naked eye or with a specially developed app based on machine learning that evaluates the color intensity. “The app also recognizes subtle differences, such as the amount of proteins present, and makes the result objectively measurable,” Dosnon explained.

Does It Really Work?

Following an initial feasibility study with volunteers, the researchers are now planning a larger field study involving more than 100 hundred people. The aim is to test MenstruAI’s suitability for daily use under real-life conditions and to compare the values measured with established laboratory methods.

Another focus is on menstrual blood’s biological diversity: the composition varies depending on the day of the cycle as well as between individuals. This heterogeneity must be recorded and analyzed—a pivotal step for clinical validation. Moreover, regulatory requirements must also be checked in order to formulate a regulatory and commercial strategy; market authorization, for example, requires a biocompatibility assessment but the materials involved are considered safe.

The team also is working with design experts from the Zurich University of the Arts (ZHdK) in an effort to further optimize the user experience and keep the psychological barrier as low as possible. “It’s also about designing the technology in such a way that makes it technically and socially acceptable,” Herrmann said.

Inexpensive, But No Substitute for a Medical Device

The technology integrated within the pad works without laboratory equipment. “Right from the outset, the aim was to develop a solution that can also be used in regions with poor healthcare provision and would be as cost-effective as possible, potentially enabling population-based screening,” Herrmann noted.

Consequently, MenstruAI can serve as an early warning system—users can seek medical advice if abnormal values are found. It is not intended to replace established diagnostics, but to help patients determine when a doctor’s visit might be expedient. In addition, health progression can be monitored over the long term and any changes can be better understood.

Herrmann and Dosnon regard MenstruAI as more than just a technical project—it is a contribution to more equitable healthcare. “When we talk about healthcare, we can’t simply phase out half of human-ity,” Herrmann emphasized.

The researchers were surprised at the extent to which menstruation is still stigmatized, including in academic circles. Many declared the idea to be nauseous or impractical. “Courageous projects are called for to break down existing patterns of behavior to ensure that women’s health finally takes the place it deserves,” Dosnon concluded.

Literature reference
Dosnon L, Rduch T, Meyer Ch, Herrmann IK: A wearable in-pad diagnostic for the detection of disease biomarkers in menstrual blood, Advanced Science (2025), doi: 10.1002/advs.202505170