Natural Cycles, an app which includes both a contraceptive and a fertility tracker, has again become the target of a regulatory investigation due to various claims made in its advertisements.

According to a statement in The Guardian, the UK’s Advertising Standards Authority has kicked off a formal investigation into the Swedish company after getting three complaints regarding the app and its paid advertising on social media sites like Facebook.

Natural Cycles was cofounded by a nuclear physicist named Dr. Elina Berglund and her husband Dr. Raoul Scherwitzl. Natural Cycles is a subscription service which includes a basal thermometer and an app. The temperature has been noted in the morning and the app’s algorithm generates insights about the user’s daily fertility. This product is a CE certified contraceptive in Europe, which raised around $30 million in funding last November.

Earlier this year, Södersjukhuset hospital in Stockholm, Sweden filed a complaint to the Medical Products Agency (MPA) after it found that 37 women among 668 became pregnant in an unplanned way while using the app. Natural Cycles advertised that it would exceed a 93 percent success rate. The company claimed that these results showed a 95 percent success rate, 2 percent higher than the advertising claims.

The company announced wrongly that the Medical Products Agency (MPA) had closed all the cases cited by Södersjukhuset hospital. It was later reported that the MPA had concluded only the first step of its investigation, and are going “to escalate the ongoing market surveillance investigation to review parts of the documentation that was compiled as a justification for the CE mark certification.” The investigation is currently ongoing.