Since its launch last year, Natural Cycles has registered more than 700,000 users in over 200 countries. But after reports of unwanted pregnancies started pouring in - one hospital linked at least 37 abortions over a three month period, an investigation has been launched into the accuracy of the app.
On its website, Natural Cycles describes itself as "an effective, natural method of contraception" and "protection with more sexual freedom - minus the side effects." It works by having users measure their temperature (with the provided thermometer) in the morning and enter the results into the app. It will then tell you whether you can have sex - green light - or are fertile and should use protection - red light.
In a first-person report for The Guardian, writer Olivia Sudjic reveals that after four-months using the app, she fell pregnant. After having an abortion, Sudjic started to investigate, finding a 2016 Guardian interview in which Natural Cycles co-founder Elina Berglund describes the ideal user as a woman in a stable relationship who is planning to have children at some point and says it's not a good option for women who absolutely want to avoid a pregnancy.
As Sudjic point out, the above isn't clear in Natural Cycles' marketing and certainly isn't shown as a warning when women download the app.
"I felt colossally naive," Sudjic wrote of falling pregnant. "I’d used the app in the way I do most of the technology in my life: not quite knowing how it works, but taking for granted that it does. Speaking to others who bought the app as contraception, it seems that many feel the same."
In response to the backlash, Natural Cycles said unwanted pregnancies are an "inevitable reality" with any form of contraception.