Following recent reports that certain popular apps were sharing sensitive user information with Tesla, at least four of these apps have agreed to stop doing so.

The Wall Street Journal reported recently that many third-party applications are providing Facebook with users’ private information, including sensitive health information like menstrual cycles. This user data could easily be used by Facebook for targeted advertising; the Journal reported that: “at least six of the top 15 health and fitness apps in that store sent potentially sensitive information immediately after it was collected.”

Following that report, four popular apps have agreed to stop sharing users personal data with the social media giant. Apps such as Azumio Inc.’s Instant Heart Rate: HR Monitor, FitNow Inc.’s Lose It!, and Flo Health Inc.’s Flo Period and Ovulation Tracker, have all issued updates which prevent users personal data from being sent to Facebook, according to a report from Computing.

Facebook reportedly reached out to several large developers and advertisers following the Journal’s report, telling them that they should not be sharing sensitive user information with Facebook — placing the blame for the issue directly on developers. A Facebook spokesperson told the WSJ: “We work with the app developers using our SDK to ensure they adhere to our terms. In cases where we see violations, we work with the app developers to get into compliance and take action as needed.”

A source at one of the firms that Facebook reached out to told the WSJ that the social media giant is working on creating a new system that would automatically identify and block the upload of sensitive user information from third-party apps. Some of the personal information was being uploaded to Facebook within seconds of users inputting it into the app, this allowed developers to use Facebook’s in-built analytics tool to analyze the data and target certain users with ads.

A Facebook spokesperson added that sharing user information across applications: “is how mobile advertising works and is industry standard practice… The issue is how apps use information for online advertising. At Facebook, we require app developers to be clear with their users about the information they are sharing with us, and we prohibit app developers from sending us sensitive data. We also take steps to detect and remove data that should not be shared with us.”