Natural Cycles, an app that uses body temperature to track a woman's menstrual cycle, has been certified as a medical device for contraception by one regulator.
The app, which records daily temperature and uses an algorithm to plot fertility on an in-app calendar, was part of a clinical study in 2016 of one million women that claimed it could be as effective as the contraceptive pill.
Now, German-based certification body Tuv Sud has approved Natural Cycles as a Class IIb medical device, the same level of certification as acupuncture needles and blood bags.
The app now claims to be the first software of its kind to be certified as a contraception alongside condoms, the pill and intrauterine devices (IUDs).
Dr Elina Berglund, co-creator of the app, said: "Women around the world are interested in exploring effective non-hormonal, non-invasive forms of contraception - and now they have a new, clinically verified and regulatory approved option to choose from."
A growing number of wearable devices and software have appeared that focus on female health and fertility, but none have previously been certified as clinically viable.
"Our high quality clinical studies, together with the required regulatory approvals, means we can provide women everywhere with a new option for contraception," Dr Berglund said.
"Natural Cycles allow women to better understand their bodies so they can make choices that are right for them."