Users accessing female health app Flo can now do so without entering their name or other identifiers that can be associated with their period-tracking and other data. 

Flo Health, which operates the popular period and ovulation tracker, said last week it had released the new “anonymous mode” feature in an effort to further protect sensitive reproductive health information.

Menstrual trackers like Flo have come under the microscope in the wake of the overturning of Roe v. Wade. App users fear that data about their fertility, missed periods and more could be used against them in states where abortion may be criminalized.

Flo’s anonymous option is one of a number of methods such apps are employing to better protect user’s post-Roe privacy. It’s not likely to ease such concerns completely, though, a privacy expert warns, due largely to the apps’ storage policies and the type of data they collect.

“Companies like to use the word ‘anonymization’ to describe taking away names or e-mail addresses or other identifiers from data, but anonymization is not a technically meaningful term,” said Justin Sherman, a senior fellow at Duke’s Sanford School of Public Policy who runs the school’s data broker project. “There are still numerous ways that that information could potentially be linked back to individuals.”

Flo, for its part, launched the feature days after Roe was struck down, saying at the time that it would become available in coming weeks. Users who opt to go into anonymous mode can still access their data, including tailored insights and predictions, without any personal information being tied to their accounts, such as name, email address or other identifiers, according to an FAQ on Flo’s website

But as its privacy policy notes, the company still stores user data in the cloud, a potentially less secure method than storing it locally on the user’s device. 

That said, Flo seeks to protect that information in a number of ways, like encrypting data as it’s transferred to Flo’s servers. In addition, data that can be used to identify someone is kept apart from data logged into the app. 

Anonymous mode is designed to provide another layer of protection by delinking all personal information, such as user ID and IP address, from stored health data. “No single party processing user data for the anonymous mode accounts will have complete information on both who the user is and what they are trying to access,” the company states.

Flo also told users they can request to have their old account deleted by emailing customer support. That means someone who has downloaded the app, used it for several months, and then wishes to delete it and download it again can start over.

Yet, such measures may not totally prevent app users from being identified, said Sherman, because device information such as IP address and mobile advertising ID, which are among the data points Flo says it collects, can be used to tie logged information back to those who entered it.

“There are certainly lots of different privacy and other statistical techniques to obscure the person behind a piece of information,” he noted. “But removing someone’s name does not prevent someone from figuring out who it is.”

This isn’t the first time that Flo has had to contend with complications related to its privacy policies.

In 2021, Flo Health settled with the Federal Trade Commission for sharing sensitive health data with Facebook despite not being transparent about that practice on its user policies. The settlement followed a 2019 investigation by The Wall Street Journal of Flo’s Period & Ovulation Tracker, which the company says has 48 million active users.

Still, the company insists it’s committed to privacy and security long term and that an audit of its privacy practices conducted in the spring as part of the FTC settlement found that its practices are consistent with its publicly stated privacy policy.

A Consumer Reports evaluation in May of this year, which included Flo and a number of other period-tracking apps in the U.S., found that they faltered when it comes to privacy, mainly because they feature cloud-based storage and allow third-party tracking. 

Additionally, a research team at the Organization for the Review of Care and Health Apps, a company that tests health apps for the UK’s National Health Service, recently found that 84% of the period-tracker apps studied share data with third parties and that nearly two-thirds share it with authorities for legal obligations.