Attorneys for the social media giant told the eight person jury the class action’s claims that Meta scooped data about the dates and lengths of users’ periods through a piece of code embedded in the Flo app called a software development kit are entirely untrue.
“Did Facebook eavesdrop?” Meta’s attorney Michele Johnson of Latham & Watkins LLP said. “Facebook never even received plaintiffs’ confidential communications, let along eavesdrop or record.”
At stake is potentially billions of dollars in damages against Meta and Flo in one of the first trials to ever address how the California Invasion of Privacy Act, enacted in the 1960s, applies to modern data sharing practices on the internet.
The trial comes as women’s health data companies face new scrutiny over their privacy policies in the wake the US Supreme Court’s 2022 decision overturning the right to an abortion.
The narrative posed by Meta and Flo during opening statements to the jury in the US District Court for the Northern District of California stood in sharp contrast to the claims of the plaintiffs, who told the jury that Flo violated its privacy policies by sharing its sensitive user data with Meta, which in turn used it to target users with advertisements driven by an algorithm.
The plaintiffs’ attorney Carol Villegas of Labaton Keller Sucharow LLP said Flo and Meta violated the privacy rights of some 30 million women who used the app.
She said the lead plaintiff, California resident and lawyer Sarah Wellman, downloaded the app in 2018 when she decided to have a second child. When first opening the app, it asked whether Wellman wanted to get pregnant, the date of her last period, and the length of her cycle along with other personal health questions.
“The moment she answered all these questions, Meta recorded whether she was ovulating,” Villegas said.
The plaintiffs, who include four other women representing a class of users who downloaded the app between 2016 and 2019, first sued Flo, Meta,
Flo, founded in London in 2015, is among the most popular period and fertility tracking apps on the market with 60 million active users. Itreached a $1 billion valuation in 2024. The startup had already faced criticism of its handling of user data before the suit, with the Federal Trade Commission reaching a settlement with Flo in 2021 requiring it to notify users of how it shared data with third parties.
Judge James Donato slimmed the class action as it made its way to trial, and Flurry, which shutdown last year, exited the case with a $3.5 million settlement. Google reached its own accord with the plaintiffs just weeks before trial. The judge certified the case as a class action earlier this year, with the class size ranging in the tens of millions.
The jury must decide whether Meta violated the California Invasion of Privacy Act, and whether Flo violated its user privacy agreements and the federal Confidentiality of Medical Information Act.
Meta and Flo’s defenses hinge on what they said was a lack of any evidence that sensitive data was shared. Like the vast majority of apps, Flo used Meta’s and Google’s software development kits, which are bits of pre-made code that allow the app to track key analytics and determine whether the app is being effective.
The companies also argued that the jury can toss out the entire case without needing to weigh in on the thorny data issues because the app’s terms of service agreement says users have only one year to file a lawsuit after learning of potential violations.
At issue in the case is 12 key app data categories used in the software development kit with names such as “R_SELECT_LAST_PERIOD_DATE.”
Meta and Flo’s attorneys said that when a user began providing information in the Flo app, it would sent send a chunk of code to Meta that simply said whether the user’s last period date was “known” or “unknown.”
“No health information, no names, no contact information, no birth dates,” Flo’s attorney Brenda Sharton of Dechert LLP said.
The case is Frasco v. Flo Health Inc., N.D. Cal., No. 3:21-cv-00757, 7/21/25.
To contact the reporter on this story:
To contact the editor responsible for this story: