Sensitive information from popular period-tracking apps has been sent to Facebook - including when users are having sex.

The information was found by Privacy International, who recently tested some of the most popular apps on Android that are used to track menstrual cycles.

They found that two apps, Maya by Plackal Tech and MIA Fem by Mobapp Development Limited, were sending users' personal details to the tech giant.

An earlier report from that other popular apps, such as Period Tracker by Leap Fitness Group and Period Tracker Flo by Flo Health, did not send information to Facebook.


Period Tracker by Simple Design Ltd and Clue Period Tracker by Biowink were also both cleared.

Period tracking apps regularly record intimate details of users' lives.

Users can input their mood, their caffeine and alcohol intake, what type of contraception they use and whether they use tampons or pads, as well as when they have sex and if they are trying to get pregnant.

The Maya app also allows users to add their own notes in a diary section - all of which are then forwarded to Facebook

This information is highly valuable to advertisers, who can use it to target products and services through Facebook ads.

"When Maya asks you to enter how you feel and offers suggestions of symptoms you might have — suggestions like blood pressure, swelling or acne — one would hope this data would be treated with extra care," the report said. "But no, that information is shared with Facebook."

After Privacy International took their concerns to developers Plackal Tech, they told the group they were removing the app's ability to send details to Facebook.

When asked about the report, Facebook told Buzzfeed that it had contacted the developers behind the apps identified in the report to discuss possible violations of its terms of service, including sending sensitive information.