Call barrier: App that turns your phone into a contraceptive

Natural Cycles, 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.

The German-based certification body Tuv Sud has now 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.”

Sexual health experts said that despite their “potential to broaden contraception choice”, fertility apps such as Natural Cycles cannot guarantee they will effectively prevent pregnancy.

Diana Mansour, vice president of clinical quality for the Faculty of Sexual and Reproductive Health of the Royal College of Obstetricians and Gynaecologists (FSRH), said more independent trials of such technology are needed.

“There are hundreds of apps which claim to help users plan or prevent a pregnancy - these come in all manner of forms and some will be more effective than others,” she said.

“Without independent evaluation we can’t say for certain which will be effective at achieving this.”

Dr Mansour warned that because Natural Cycles is an awareness-driven app, there is room for error in its use.

“Women who wish to use fertility awareness-based contraception are advised to receive guidance from a qualified teacher to learn how to effectively monitor the different indicators.

“Apps currently do not come with this teaching, leaving room for misunderstanding and inaccurate use.

“As well as requiring regular, consistent monitoring of fertility indicators, all fertility awareness-based contraceptive methods rely on women abstaining from sex or using condoms correctly during the fertile window. If women don’t follow these instructions perfectly, their risk of pregnancy greatly increases.”