Researchers at ETH Zurich have developed the first technology capable of recognising biomarkers in menstrual blood, directly in sanitary towels. MenstruAI promises a simple, non-invasive method for recording health data in everyday life.

The study is published in the journal Advanced Science.

The application is straightforward: wear a sanitary towel with the integrated, non-electronic sensor, take a picture of the used towel with your smartphone, and use the app to analyse it. MenstruAI is designed to enable users to check their health regularly and effortlessly. For the first time, a new technology from ETH Zurich brings a tracking tool to a place where hardly anyone would expect it: the sanitary towel.

Menstrual blood is a source of information

Over 1.8 billion individuals menstruate, yet menstrual blood plays a little role in medicine. "This reflects a systemic lack of interest in women's health," states Lucas Dosnon, first author and doctoral student in the group of Inge Herrmann, a professor at the University of Zurich, Balgrist University Hospital, 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," says Dosnon.

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

The ETH researchers used three biomarkers as a starting point for MenstruAI. They currently measure the C-reactive protein (CRP) as a general inflammation marker, the tumour marker CEA, which is typically elevated in various cancers, and CA-125, a protein that can be elevated in endometriosis as well as ovarian cancer.

Many more protein-based biomarkers are currently being investigated and will be added to the list to reflect many other aspects of an individual's health.

The same functionality as a COVID test

MenstruAI utilises a paper-based rapid test strip, a principle familiar from COVID self-tests—however, analysing blood instead of saliva.

When the biomarker in menstrual blood contacts a specific antibody on the test strip, a colored indicator appears. The colour intensity varies depending on the concentration of the corresponding protein.

The higher the concentration, the darker the colour. The test area is embedded in a novel, small, flexible silicone chamber, which can be combined with a commercially available sanitary towel. Thanks to its innovative design, only a controlled volume of blood reaches the sensor, preventing smearing or falsification of the test.

The results can be read visually or with a specially developed app based on machine learning that evaluates the colour intensity. "The app also recognises subtle differences, such as the amount of proteins present, and makes the results objectively measurable," explains Dosnon.

Does it work in everyday life?

Following an initial feasibility study with volunteers, the researchers are planning a larger field study involving over one hundred people. The goal is to test the suitability of MenstruAI for everyday use under real-life conditions and to compare the measured values with established laboratory methods.

Another focus is on the biological diversity of menstrual blood: the composition varies depending on the day of the cycle and between individuals. This heterogeneity must be recorded and analysed—a pivotal step for clinical validation. Additionally, regulatory requirements must be addressed, such as biocompatibility assessments. The materials involved are considered safe.

Simultaneously, the team collaborates with design experts from Zurich University of the Arts (ZHdK) to further optimise user experience and reduce psychological barriers. "It's also about designing the technology to be both technically and socially acceptable," says Herrmann.

Inexpensive, but no substitute for medical advice

The technology integrated within the pad operates without laboratory equipment. "From the outset, the goal was to develop a solution suitable for regions with limited healthcare infrastructure and to be as cost-effective as possible, potentially enabling population-based screening," says Herrmann.

Consequently, MenstruAI can serve as an early warning system—users can seek medical advice if abnormal values are detected. It is not intended to replace established diagnostics but to provide information on when a medical consultation might be advisable. Additionally, health progression can be monitored over time, and changes can be better understood.

Herrmann and Dosnon view MenstruAI as more than just a technological innovation; it is a contribution to more equitable healthcare.

"When we talk about healthcare, we can't simply exclude half of humanity," Herrmann emphasises. The researchers were surprised by the extent to which menstruation remains stigmatised, even within academic circles, and by the negative reactions to their idea, which some deemed nauseous or impractical.

However, Dosnon is convinced: "Courageous projects are needed to break down existing patterns of behaviour and ensure that women's health finally receives the attention it deserves."