Het Parool on PERIOD.: 'I don't want money to be made from women's data'

Het Parool, one of the largest Dutch newspapers, published a feature on PERIOD. on Lisa (29) who built the app, and on a much bigger conversation: what do commercial period apps actually do with the most intimate data you share? Read the full article (Dutch) →

What the article is about

The reporter spoke with Lisa Volkers about why she built PERIOD. and with legal scholar Judith Blijden (host of the podcast series The Digital Period) about the broader picture: privacy terms no one reads, period data that legally counts as "special category data," and a commercial market where women's bodies have been a business model for years.

1. It started as frustration

"It had been a frustration of mine for years that I kept running into things in my cycle but never really understood them. At some point I thought: how can I be 29 and still not know my own body?", Lisa Volkers in Het Parool (translated)

The existing apps were "all very pink, full of push notifications and pop-ups. And in the end you couldn't really do anything without paying." So Lisa built her own, with her partner, in three months: PERIOD. A Dutch, privacy-first cycle app with no paywalls.

2. The real issue: data as a business model

In recent years, journalists have repeatedly scrutinised how large period apps handle user data: information about ovulation, pregnancy and sexual activity leaving the app through third-party SDKs. That debate is exactly why we designed PERIOD. differently.

"This is about extremely personal information. About miscarriages and abortions. It goes way further than how many steps you took.", Lisa Volkers in Het Parool (translated)

Judith Blijden explains why this matters: period data legally counts as "special category data", sensitive information that should be extra protected. "That data can be incredibly valuable for advertisers. Especially anything around pregnancy."

When abortion rights were rolled back in parts of the United States, American women deleted period apps en masse out of fear that their data could be used against them. In 2023 UK police even requested user data from period apps after "unexplained miscarriages." This isn't theoretical.

3. How we do it differently

Privacy isn't a feature for PERIOD. it's the starting point. Concretely:

• 🔒 Encrypted backup on EU servers, under GDPR.
• 🛡️ Your data stays yours. No ad networks, no data brokers, no "anonymized" resale.
• 💸 No paywall on the basics. Cycle, symptoms, phases, predictions, free.
• 🤖 AI only with explicit consent. And your conversations aren't used to train AI models.

The full breakdown is in our privacy policy and, if you want it in plain language, in our blog Privacy at PERIOD. vs. other cycle apps.

4. Pink, patronising, and not built for everyone

Beyond privacy, the article also covers how many apps shape "femininity." Pink interfaces, cute illustrations, a stereotypical idea of "the female user."

"It's as if someone thought: it's for a woman, so it has to be pink with rainbows. I use these apps because I want information about my body. So I just want to be taken seriously.", Lisa Volkers in Het Parool (translated)

Blijden adds that many apps assume a very narrow definition of who a user is: heterosexual women between twenty and forty. "Menopause barely exists. Some apps don't even account for women who have sex with women."

5. Not just an app, a movement

Within two weeks of launch, PERIOD. had ten thousand users, no ad budget, no marketing campaign. Het Parool closes with this line from Lisa:

"Then I realized: this isn't just an app. It's actually a movement.", Lisa Volkers in Het Parool (translated)

We agree. The basics of PERIOD. stay free and accessible. There is now a paid layer with extras, PERIOD. plus, so the basics remain available to everyone. And we're building partnerships with NGOs to make period education more accessible internationally.

Read the full piece

The full article is at Het Parool (Dutch): Amsterdamse Lisa (29) ontwikkelde menstruatie-app PERIOD.: "Ik wil niet dat er geld wordt verdiend aan data van vrouwen".

If you're wondering how PERIOD. works or why it's different, download the app from your App Store or Play Store, and read our privacy policy. No marketing fluff, just what actually happens with your data.