"Will Sanitary Napkins Become 'Cancer Tests'? Could Menstrual Blood Transform Medicine?"

"Is Menstrual Blood Something to Be Discarded?"—The Dawn of an Era Where "Pads Become Test Kits"

For a long time, menstruation has been made "invisible." In advertisements, the color of blood is replaced with blue, prioritizing cleanliness and odorlessness. WELT introduces research that directly addresses "menstrual blood (Menstruationsblut)" as a clue to diseases, which has been left behind in the extension of such taboos. A symbolic event cited is the turning point when a hygiene product manufacturer shifted its advertising expression from "blue liquid" to the real red in 2021.DIE WELT

Why is menstrual blood, which has been difficult to become the main subject of research, now attracting attention as a "treasure trove of medical data"? The key lies in its nature as **"a body fluid that can be collected every month, non-invasively, and continuously."**

Embedding "paper test strips" in sanitary products—The Mechanism of MenstruAI

The WELT article focuses on the "biomarker detection within sanitary napkins" being advanced by Swiss researchers. The concept is surprisingly intuitive, akin to a "blood version of a rapid antigen test." By incorporating paper-based test strips into the napkin, users can visually or photographically capture the color change (line) that appears after use, and quantify it through an app. WELT explains it as "analyzing blood instead of saliva like a Covid test."DIE WELT

This technology is called "MenstruAI," and ETH Zürich's announcement emphasizes the design of determining color changes with a smartphone without placing electronics on the napkin (electronics-free) .ETH Zürich

In other words, it aims to capture "signals from the body" as an extension of daily life, without relying on special blood collection devices or laboratories.

What Can Be Detected?—Three Biomarkers (CRP/CEA/CA-125)

According to the WELT article and ETH information, the prototype initially targets the following three biomarkers:

• CRP: Known as an indicator of inflammation

• CEA: A tumor marker that can increase in cancer

• CA-125: Can increase in endometriosis or ovarian cancerDIE WELT

The important point here is that it is not a matter of "immediate cancer if elevated." Biomarkers can fluctuate due to physical condition, cycle, inflammation, benign diseases, etc. WELT also mentions that researchers caution, "High values do not necessarily mean disease," while discussing the potential for a pathway of **"initial check at home → appropriate medical examination for those in need."**DIE WELT

Similarly, reports (derStandard) also clarify the intent to "function as an early 'alarm (early warning)' rather than replacing diagnosis."DER STANDARD

Menstrual Blood as "Information-Rich Body Fluid"—Why Has It Been Overlooked Until Now?

ETH Zürich's announcement describes the current situation where menstrual blood has been scarcely addressed in medicine, despite the large number of people experiencing menstruation worldwide, as a "reflection of systematic indifference to women's health." Furthermore, menstrual blood contains numerous proteins and can sometimes be compared at concentrations close to venous blood.ETH Zürich

In short, despite having the potential to be a **"monthly blood sample,"** it has been left behind due to societal aversion, shame, and biases in research funding and interest. This distortion is now being rediscovered within the trend of Femtech (women's health × technology).

Research Is Not Limited to Switzerland—Stanford and Startups

The WELT article also touches on a 2022 study by Paul Blumenthal, a gynecologist at Stanford University in the U.S., introducing the potential detection of HPV (including high-risk types related to cervical cancer risk) and HbA1c , important for diabetes management, from menstrual blood. He is reported to have stated that "blood is not waste but has health value."DIE WELT

Moreover, the market is moving outside universities. Companies like Qvin (Q-Pad) in California and Theblood in Berlin, which advocate testing and analysis using menstrual blood, are emerging. The founder of Theblood, who has endometriosis, positions menstrual blood as a "non-invasive, monthly, widely accessible" means and expresses a desire to change the current situation where women's health issues are "hard to visualize."DIE WELT

Barriers to Popularization—Accuracy, Standardization, and the "AI in the Underwear" Issue

On the other hand, the hurdles are high. According to WELT, the research team had to start with "basic understanding of menstrual blood as a specimen" alongside technological development, with the lack of literature being an initial stumbling block.DIE WELT

Additionally, social resistance cannot be ignored. Researchers have received critical messages, including opposition to targeting only women and concerns about "AI in the underwear (KI in der Unterhose)."DIE WELT

This issue encompasses more than just a dislike of technology.

• Privacy: Resistance to handling highly sensitive information like menstruation through smartphone photography and app analysis

• Data Handling: Concerns about where analysis images and health data are stored and who can access them

• Amplification of Anxiety: The possibility that self-checks may not only provide "reassurance" but also lead to "excessive worry"

Furthermore, realistically, there are challenges related to price, regulation, and insurance coverage. WELT mentions plans for a field trial involving over 100 people and, if successful, the possibility of market launch by the end of 2027 , while stating that insurance subsidies are undecided.DIE WELT

Can It Become a "Supplementary Line to Fill the Gaps" Rather Than a "Substitute for Health Checkups"?

The goal of such technology is likely not to replace hospital tests but to **"fill the gaps in areas that are easily overlooked."** For example, endometriosis is said to sometimes take time to diagnose, and there are many anecdotes of symptoms being dismissed. If regular data derived from menstrual blood can serve as a trigger for consultations or material for dialogue with doctors, there is potential to narrow the disparity in medical access.

Particularly, as WELT suggests, if it functions as a "simple primary screening" in areas with scarce medical resources, the impact would be significant.DIE WELT
However, for that to happen, it is essential to design not only "accuracy" but also "consultation pathways in case of false positives" and "accountability."

Reactions on Social Media (Emerging Points of Discussion)

The theme of this article tends to generate relatively "heated" discussions on social media. In fact, positive reactions are gathering on LinkedIn, mainly from those involved in Femtech.

• "It's Strange That It Has Been Ignored Until Now"
  There are voices expressing surprise at the abundance of information contained in menstrual blood, with a sense of problem that "other body fluids have been thoroughly analyzed, but menstrual blood was delayed."LinkedIn

• "'Menstrual Blood Is Not Waste' Resonates"
  One comment welcomes the value shift itself, stating, "Just the sentence 'Menstruationsblut ist kein Abfall' shows how delayed the change has been."LinkedIn

• "I Want to Live in Such a Future"
  There are also reactions that perceive it as an expectation for a society where "women's health is properly measured," rather than debating the pros and cons of the technology.LinkedIn

On the other hand, as introduced by WELT, researchers have also received resistance to "AI entering underwear" and opposition to targeting only women.DIE WELT

The pros and cons on social media ultimately connect to discussions about societal design, not just about whether the technology is amazing, but about how to handle bodily taboos/data rights/gender gaps in healthcare .

Points to Watch Going Forward

The next focus is clear.

1. Whether reproducibility can be achieved in everyday environments in field trials involving over 100 peopleDIE WELT

2. For which diseases and uses "clinically meaningful accuracy" can be achieved

3. Whether privacy and accountability can be placed at the center of the product

The future where "sanitary products become test kits" sounds sensational. However, the