08/04/2025 12:33 p.m.

Understand your Ovulation Cycle and Learn More About your Body

Dr. Niels van de Roemer
Dr. Niels van de Roemer Medical Adviser

With Daysy you get to know your individual ovulation cycle.

The ovulation cycle is an important component of your femininity and your body. In many complex and interacting processes, it enables the creation of new life. Even when you are not currently ready for a baby, it helps to know your own cycle to regain a feeling of closeness to your body and yourself. Every woman's ovulation cycle is individually different, but still essentially alike. The main phases always appear in the same order. But the length of the individual phases, such as the duration of the period or the interval until ovulation, vary from woman to woman. Knowledge of your monthly cycle can help you to conduct your life in harmony with your natural rhythm and use contraception only when required. If you know when you are fertile, you also know when to use contraception. With Daysy you have a reliable assistant in calculating your fertility.

Calculating a woman's monthly ovulation cycle with Daysy

Daysy is a highly modern fertility tracker that can calculate a woman's monthly cycle. All you have to do is take your basal temperature before you get out of bed in the morning. Activate Daysy via the push of a button, put the test prod underneath your tongue and wait until a signal declares that the measurement is over. Then Daysy might ask you to confirm that you have your period via the simple push of a button. Then you’re done! Daysy now displays your fertile status for the current day. The display is a colourful light that is either red, green or yellow. Yellow will be shown to you mainly during Daysy's learning phase. When the red light is on, it means that you are currently fertile / possibly fertile. The green light means that you are not currently fertile.

Ovulation cycle: Consciously enjoy your womanhood

If you want to learn more about your body beyond your current fertility status, synchronise Daysy with the free app "DaysyDay" for more additional interesting information about your ovulation cycle directly on your smartphone. You can get a look at your temperature curve or a preview of the next month. This helps you to adjust the timing of your free time even better to your monthly cycle. 

Let Daysy calculate your ovulation cycle and enjoy a hormone-free life in harmony with your body and your femininity!

What is the best way to measure?

For optimal use of Daysy, we recommend that you should have slept sufficiently (at least one hour) before the measurement. It is important that you take your temperature immediately after waking up, before getting up and becoming active. Measure below your tongue, with your mouth closed, and keep the device steady while it is measuring. Video Tutorial

Do I have to measure at the same time every day?

No. You should have at least one hour of good quality sleep before the measurement. It is important that you take your temperature immediately after waking up, before getting up and becoming active. For optimal use of Daysy, try to get at least 3 or more hours of sleep before measuring. Less sleep can result in more temperature fluctuations causing Daysy to give more fertile or potentially fertile days.

How do I enter or edit menstruation?

You can confirm or remove menstruation at any time during the current day. Simply press the button to turn on your Daysy, and then press and hold the activation button until the violet light lights up without flashing and you hear a "beep." Confirm you are menstruating for each day of active bleeding and for a minimum of three consecutive days. You can also remove menstruation data for the same day by turning Daysy on and pressing and holding the activation button until the purple/blue light is no longer solidly lit and begins flashing again.

Video Tutorial

How long until Daysy knows my personal cycle?

The first 2-4 cycles of use are considered Daysy's learning phase. Over the course of her learning phase, Daysy will come to understand your cycle and begin narrowing down your fertile window. Daysy remains quite cautious and conservative during this time, which is why Daysy is accurate starting the very first day.

When can I start to rely on Daysy's results?

You can rely on Daysy's results starting the very first day of use. In the beginning, you will see more yellow and red days because Daysy is still learning your unique cycle. You will see more green days as Daysy comes to understand your cycle and can narrow down your fertile window. The more regularly you measure, the better.

My cycle is irregular. Can I still use the devices?

Yes. Irregular cycles are not a problem for Daysy/Lady-Comp. Even with irregular cycles, all Valley devices distinguish between non-fertile and fertile days with a very high accuracy. However, in case of extreme fluctuations between cycles it will give you more red and yellow lights and less green lights. Fluctuations of several days are usually not a problem. If you have questions about your unique cycle, please reach out to our team of experts.

Are there any costs associated with the DaysyDay app?

No! DaysyDay is free! There are no in-app purchases or upgrade fees.

Does illness reduce the reliability of the device?

In general, you should skip measurements during illness and while you are taking medication that can have an influence on your body temperature or cycle. If you have doubts, contact your doctor or our customer service team.

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Get more information

If you’re ready to start a family, read on to learn helpful tips to enhance your fertility and prepare for pregnancy.

The fertility tracker method is a modern, digital evolution of natural family planning. It eliminates common sources of error – ensuring ovulation is accurately detected and recorded.

Below, we’ll show you how traditional NFP (Natural Family Planning) rules differ from the features of modern fertility monitors – and how the two compare.