Daysy and Lady-Comp: Fertility Trackers Built to Medical Standards
Daysy has been developed and certified as a medical device. Not every fertility tracker on the market meets this standard, which requires a rigorous quality management system. Precision and reliability are at the core of everything Daysy does.
Valley Electronics AG, the Switzerland-based company behind Daysy, holds certification to EN ISO 13485, meaning its quality management system meets the latest standards for medical products. All processes at Valley Electronics AG are subject to regular internal and external review, enabling continuous improvement across its range of fertility trackers.
Valley Electronics AG is also registered with the FDA and must comply with medical device regulations, which are subject to regular inspections at their Zurich office and across their supply chain. In addition, an independent European Notified Body audits the quality management system annually.
The Daysy and Lady-Comp Algorithm
Daysy and Lady-Comp determine your fertile and infertile days using a proprietary algorithm built on an extensive database. Drawing on five million menstrual cycles and more than 30 years of research, including multiple clinical studies, the algorithm delivers reliable, personalised cycle information.
The accuracy of this algorithm has been independently tested. A scientific study evaluated 107,000 cycles (basal temperature and menstrual input) from 5,328 women in Germany and Switzerland over a ten-year period.
The independently reviewed result: Daysy and Lady-Comp achieve an overall accuracy of 99.4% in distinguishing non-fertile days from fertile days.
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Only 0.6% of days displayed as green (infertile) fell within the actual fertile window and should have been shown as red. Notably, 50% of these false green days occurred five days before ovulation, a point in the cycle where the probability of pregnancy is minimal (see graph).
The algorithm works by combining three elements: acquiring and learning from new data (your daily BBT, menstruation start and end, and accumulated cycle history), and applying statistical analysis such as identifying the temperature rise that follows ovulation.
After an initial learning period, the algorithm begins predicting ovulation and opens the fertile window (red days) at least five days before the earliest possible ovulation date (figure 1A). Once a temperature rise is detected and ovulation is confirmed, Daysy and Lady-Comp display subsequent infertile (green) days through to the next menstruation (figure 1B).
figure 1 A
figure 2 B
In the background, the algorithm accounts for each measurement against your previous average temperature, allowing it to tolerate occasional outliers or missed readings. If there isn't enough data to display a confident red or green result, Daysy shows a yellow indicator and factors the fluctuation into the following cycle's calculations.
In short: Daysy and Lady-Comp learn from you over time.
Precise Temperature Measurement
Daysy and Lady-Comp use a highly sensitive thermal sensor to measure basal body temperature. What sets this sensor apart is that it waits for the temperature to fully stabilise before recording a result, which can take up to 60 seconds.
The sensor warms up prior to measurement to ensure accuracy. If the temperature dips during the reading (for example, due to cold air entering the mouth), the sensor waits for it to rise and stabilise again before completing the measurement. This approach sets Daysy and Lady-Comp apart from standard basal thermometers, which simply record the temperature at a fixed point in time.
Our Commitment to Accuracy and Quality
Valley Electronics AG has been a pioneer in fertility tracking technology for over three decades, with 500,000 users worldwide. By partnering with them, we bring together a long track record of reliability with the latest advances in femtech.
Daysy was the first fertility tracker to be paired with a companion app. The updated Daysy 2.0 won the Red Dot Design Award in 2019.
We are committed to offering the most accurate and well-designed fertility trackers available, and we continue to invest in improving Daysy so that it works as well as possible for every user.
