Natural Cycles: contraceptive app blamed for 37 unwanted pregnancies

App used by 125,000 UK women calculates fertility with mathematical algorithm

Natural Cycles app
(Image credit: Natural Cycles)

A contraceptive app is being investigated after 37 women seeking abortions blamed it for their unwanted pregnancy.

A Stockholm hospital filed a complaint with the Swedish Medical Product Agency over the Natural Cycles app after it was linked more than three dozen terminated pregnancies in the last four months of 2017, Swedish broadcaster SVT reports.

The app was created by physicist husband and wife, Elina Berglund and Raoul Scherwizl, in 2014 and claims to be able to predict a user’s fertility on any given day with near-perfect accuracy using a mathematical formula.

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In August 2017, Natural Cycles became the first and, so far, only contraceptive app to be approved as birth control by the EU.

More than 700,000 women use the app as an alternative to invasive contraceptive methods, 125,000 of them British, says The Daily Telegraph.

A spokesman for the company said that the reports of three dozen unwanted pregnancies “are not surprising given the popularity of the app and in line with our efficacy rates”.

"As our user base increases, so will the amount of unintended pregnancies.”

Nonetheless, the company told Fortune that it had launched an internal investigation into the reports from Sweden.

The company claims the mathematical method is 99% effective at preventing pregnancy - but only if used correctly.

A 2015 clinical study found that “more than half of the women who got pregnant while using the app had unprotected sex with men on the days when the app advised against it”, Business Insider reports.

Used “typically”, which allows for occasional human error on the part of the user, Natural Cycles is 93% effective, making it about as reliable as the contraceptive pill, and significantly more reliable than condoms, according to NHS statistics on typical use.

The app, which costs £5.99 a month and comes with a thermometer, works by asking users to enter their temperature every day and record the beginning and end of their period each month.

An algorithm on the app then calculates whether it is a “green” day, when users can have unprotected sex with minuscule risk of pregnancy, or a “red” day, when they should either abstain or use contraception.

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