Period tracking apps help you track your menstrual cycle, so you know when to expect your period. They’re growing in popularity worldwide, with the three most popular ones racking up over 250 million downloads between them. But studies show that some women might also be using them to avoid getting pregnant.

One of the apps, Natural Cycles, has been approved in the US to be used as a contraceptive. The company claims it is 93% effective at preventing pregnancies, when used perfectly. So why are more people turning to these apps? Are they safe to use as a contraceptive and what are the risks?

Sexologist Rayka Kumru from Turkey explains why these period tracking apps are becoming so popular and the privacy concerns around using them. Dr Francesco Rampazzo, a lecturer in Demography at the University of Oxford, tells us more about where period tracking apps are getting the most downloads.

Instagram: @bbcwhatintheworld