It’s green light go, red light no:

The femtech that’s putting power over fertility in women’s hands


The current trend toward hormone-free contraception is spurred on by the lack of side effects, but women still need safety and effectiveness. A new study by Valley Electronics AG and the University Women's Clinic Erlangen now proves: in preventing pregnancy, women can put their trust in the unique combination of a fertility tracker and an app with 99.4% percent accuracy.

More and more women want to avoid hormonal contraception and are choosing hormone-free methods of pregnancy prevention instead. Many now use mobile apps to track their fertility status. However, experts have warn of the use of these “fertility apps” alone, as few are as effective as they claim1 A reliable alternative is femtech in the form of a fertility tracker. The fertility tracker records, save, and analyzes changes in the female cycle in order to quickly, simply, and safely indicate fertile and non-fertile days with a colored light.

The fertility tracker, Daysy, by the Swiss medical technology company, Valley Electronics AG, can be used on its own, or, uniquely, in combination with the DaysyView app. The one-button, easy-to-use design makes the Daysy fertility tracker highly effective by avoiding the opportunity for user error. A new study by Valley Electronics AG, in collaboration with the University Women's Clinic Erlangen,  shows that combining the Daysy fertility tracker and the optional DaysyView app helps users to distinguish fertile from non-fertile days with 99.4% accuracy.

According to Dr.Martin C. Koch, the principal author of the study, “combining the Daysy fertility tracker with the app has again improved the safety with which pregnancies are prevented to 99.4%.”

The professional journal 'Ärzteblatt' reported that the use of fertility apps alone can easily lead to incorrect results.1 These stem from the user wrongly inputting data or from errors in the more glitch-liable software . In the eyes of experts, when used alone, fertility apps, are not safe for contraception and can only be trusted for planning pregnancy.

Simple, side-effect free, and highly effective

The Daysy fertility tracker is a medical device, certified according to CE/ISO standard. Every morning after waking up, the Daysy measures the user’s temperature underneath the tongue, records it, and directly displays to the user whether they are experiencing a fertile or an non-fertile day as a colored light. Green indicates non-fertile days, red indicates fertile days, and yellow indicates the device's initial learning period. With an internal database of millions of cycles, Daysy 'learns' to identify the individual’s unique cycle with the help of a complex algorithm. With the app, DaysyView, users can transfer their recorded data onto their smartphone or tablet to display their personal cycle calendar, temperature curve, and statistics, and predictions. The user can also share this information with a partner or with a health practitioner.

USD 330.00

Daysy calculates your fertile and infertile phases with an accuracy of 99.4%.

Daysy calculates your fertile and infertile phases with an accuracy of 99.4%.

  • Fertility tracker Daysy (incl. battery)
  • Connection cable for your smartphone
  • Instructions for use


Safety proven in clinical studies

An independent clinical study has already shown that the Daysy fertility tracker calculates and indicates fertile and infertile days with a 99.3% safety. Valley Electronics AG and the University Women's Clinic Erlangen recently conducted a new clinical trial to ascertain if this effectiveness level could be increased through the use of  the DaysyView app in combination with the Daysy fertility tracker. In this retrospective study, 800 users of the Daysy fertility tracker worldwide were surveyed from the beginning of November to the end of December 2016. The participants answered questions about their individual cycle, their experience with contraception, pregnancy, family planning, and their use of the DaysyView app.

According to Dr.Martin C. Koch, the principal author of the study, “combining the fertility tracker with the app has again improved the safety with which pregnancies are prevented to 99.4%.”“The study shows that the additional use of the app improves the application, the understanding, and the proper handling of the Daysy fertility tracker,” explains Dr. Stefan Renner, the director of the study and deputy head of the University Women's Clinic Erlangen. “Thereby the combination of a Daysy fertility tracker and the DaysyView app provides  greater awareness of the user’s cycle and promotes more involvement in the use of the fertility tracker.”

Displaying the user’s cycle on the app helps users of the Daysy fertility tracker get to know their body and cycles better. This body-awareness has a positive effect on the correct use and, therefore, the safety of the Daysy fertility tracker.


Effectiveness of contraceptives

The effectiveness of every contraceptive, as well as fertility trackers, is based on the Pearl Index (PI). This is calculated by how many pregnancies occur in a group of 100 women in the course of one year. For example: if one out of 100 women who use the same method for one year becomes pregnant, the Pearl Index is 1.0. If two women become pregnant in one year, it is 2.0. This means that the lower the Pearl Index, the safer the contraceptive.


There is a  'method related Pearl Index' and a 'user related Pearl 

Index.’ The user related Pearl Index refers to how the method is typically effective with every day, normal use. The bigger the difference between the method related Pearl Index and the user related Pearl Index number, the more important it is to use a method correctly. The smaller the difference between the two Pearl Index numbers, the less opportunity there is for user error with this method.

The new study by Valley Electronics AG and the University Women's Clinic Erlangen has now shown that the method related Pearl Index of the Daysy fertility tracker improves from 0.7 to 0.6 through the additional use of the DaysyView app. Daysy is, as such, 99.4% accurate at indicating fertile days, when the user can choose a barrier method like a condom or diaphragm.

The current study also proves the user related Pearl Index of the Daysy fertility tracker. By using the DaysyView app in addition to the Daysy fertility tracker, the user related Pearl Index improves by more than half – from 3.8 to 1.3 when compared to the previous study.3 This means that Daysy and the DaysyView app are highly effective during everyday, normal use.


Daysy Clinical Study 2018.pdf (937.4 KB)

Commentary on the content and background of the independent clinical study.pdf (109.8 KB)