The menstrual cycle data gap: why what we can’t measure still shapes women’s lives From flawed testing methods to femtech innovation
It is difficult to find an experience that is at once more universal and more individual than the menstrual cycle. Not only because it varies from person to person, but because it is hard to measure, standardise, or translate into data. And when something cannot be measured, it often stops existing at a systemic level: without objective parameters, it becomes difficult to define what a “normal” flow is, when bleeding is excessive, or when pain deserves clinical attention. The consequence is tangible: fewer diagnoses, less medical recognition, and fewer workplace protections. What cannot be quantified is rarely claimed or regulated. A gap that affects the daily lives of far more women than one might imagine.
The history of menstrual products: from an accidental discovery to new testing methods
The way we manage periods has always been the result of adaptation rather than intentional design. The first modern sanitary pads, in fact, emerged from a decidedly non-female context: during the First World War, nurses began using cellulose gauze originally intended for treating soldiers’ wounds to absorb menstrual blood as well. An invention born out of necessity, derived from materials designed for entirely different bodies and purposes. Since then, product development has continued steadily, but not always alongside an equally rigorous understanding of the phenomenon it was meant to address.
Recent research history makes this particularly clear. Pads, tampons and internal devices have existed for about a century, yet only in 2023 did a study begin testing them using real menstrual blood instead of the saline solutions previously used. This is not a technical detail: menstrual blood has a completely different viscosity and composition. It changes how it is absorbed, distributed, and retained. And therefore, it changes the performance of the products designed to contain it. For obvious reasons, for years the focus was placed more on safety than on accuracy. In the 1980s, for example, cases of Toxic Shock Syndrome linked to high-absorbency tampons surged, prompting urgent revisions of materials and guidelines. But that public health crisis, while crucial, did not lead to a more precise understanding of the cycle itself: it made products safer, but not necessarily more aligned with the biological reality they were meant to manage.
Will the gender data gap ever be closed?
The consequences do not only concern product effectiveness, but the way menstruation is understood. Or, more precisely, not understood. If the tools used to measure a phenomenon are inaccurate, the resulting data will be too. And if the data is fragile, everything built upon it becomes unstable: from medical guidelines to individual perceptions of what is “normal.” In this sense, menstrual products are a concrete example of what Caroline Criado Perez defines in her book *Invisible Women* as the gender data gap. In recent years, something has begun to shift. At CES 2026, for instance, FlowPad was presented, a prototype “smart” pad capable of analysing menstrual blood to monitor hormonal parameters and flag potential anomalies. It is an example of how femtech is trying to turn the cycle from an invisible event into a source of data. But one question remains: what value do these innovations have if the scientific foundation they are built on has, until very recently, been so fragile?
The marketing of menstrual products
Meanwhile, the menstrual product market has expanded. Alongside traditional products, there are cups, discs, period underwear, reusable and hybrid solutions. Yet their adoption is still limited, and general awareness surprisingly low. Marketing oscillates between two extremes: on one side, an aesthetic that continues to avoid any realistic representation of blood; on the other, a pseudo-empowerment narrative that often slips into paternalism. It is no coincidence that the word “period” was first spoken on television only in 1985, in a Tampax ad featuring Courteney Cox. Not that long ago; and this cultural delay is still reflected today in the way menstruation is discussed, represented, and studied.
Recognising invisible infrastructures
Talking about discrimination, then, means shifting the conversation. It is not only about stigma or taboo, but about invisible infrastructures: missing data, incomplete protocols, undefined standards. As long as the cycle remains difficult to measure, it will remain difficult to recognise. And as long as it remains difficult to recognise, it will continue to be treated as a private, individual, almost optional issue. As if menstruation were a choice women make every month. The point here is not simply to “break the taboo.” It is to build better tools to observe what already exists. Because as long as blood remains an abstraction - simplified or replaced - everything else will remain one too. Except its impact on women’s lives; that, it does not.