week 20 - Mobile app that replaces the pill approved as contraceptive - can you trust it?

 A mobile app has been granted medical approval to be used as a contraceptive in the European Union in a breakthrough that could spell the end for hormonal and intrusive birth control measures. 

Natural Cycles is a fertility tracking app that tells users whether they're fertile or not by monitoring their temperature. Used by 150,000 around the world, it has received approval from Tuv Sud, a certification body, to be marketed as a medical device for contraception. The stamp by a body within the European Economic Area approves it for use in the UK. 

It is the first time that such technology has been classified as being effective in preventing pregnancy. Similar to the natural planning or "rhythm" method, the app tells users how fertile they are on a given day and says whether they can or cannot have sex without being at risk of pregnancy. 

The Natural Cycles app works in conjunction with a thermometer and algorithm to determine whether users are fertile on any given day. For it to work accurately, women must take their temperature every morning and enter it into the app. Because of minor temperature fluctuations after ovulation, which increase by up to 0.45C, the app can tell the days users will be fertile.

 It was created by Nobel Prize winning physicist Dr Berglund and her husband Dr Raoul Scherwitzl who used their mathematical backgrounds to design an algorithm that can learn individual women's temperature fluctuations over time.