Frequently asked questions

Technical Questions & Troubleshooting

What is the activation button?

The activation button is your way to tell daysy to turn on, measure your temperature, and enter menstruation data.

I took out my battery, where did my data go?

The battery should only be taken out, when Daysy signals you to do so, in which case the battery should be changed according to instructions. However, if you took the battery out and did not immediately replace it with daysy having been left for a long time without any power, Daysy has no way of tracking what day it is, even though the data is safe. Daysy’s internal calendar doesn’t synchronize with the calendar on DaysyView.

When power is reapplied, Daysy still uses all the old cycle data, but waits for the first mens day to re-synchronize with your cycle.

For now, DaysyView simply hides the old data because it’s not 100% sure on which calendar days it should display it. We understand this may be frustrating to you, and are working on a solution in a future version of daysyView.

There’s a simple work around though. Just don’t take the battery out of daysy! We’ve done extensive testing and generally we haven’t found a strong reason ever to do this. The battery lasts for > 2 years (and Daysy warns you with enough time to spare about changing it) and the software in Daysy is very stable.

If you have trouble communicating with DaysyView, the problem most likely lies with the mobile App. With each release of DaysyView, we work to make this communication more stable, but on occasion something slips through. Please check out the DaysyView FAQ items, and if you’re stuck, we’ll be happy to help you through e-mail or on the phone.

How can I connect daysy with my phone?

Open daysyView on your phone and follow the instructions provided in the App. Once on the Calendar display, connect the provided TRRS cable to daysy. If daysy does not wake up by herself, press the activation button to do so. Now connect the other end of the cable to your phone and wait for daysy to sync.

What if I have a very small temperature step?

If, for some reason, the temperature step is too low, daysy will maintain red lights for a longer period of time and then shift to yellow before changing to green again.

Small temperature steps may be indicative of hormonal imbalances. A monophasic cycle will have no temperature step because ovulation did not occur. Corpus Luteum Insufficiency (CLI) will also cause a slight or unrecognizable temperature step because the body is not producing high enough levels of progesterone to cause the BBT to rise.

Women experiencing perimenopause may notice smaller temperature steps as the levels of estradiol and progesterone decline. It is also possible that a small temperature step is the result of “noisy” temperature readings. Be sure to hold the sensor very still under your tongue and keep your mouth closed as you record your temperature. Always try to record in the same place within your mouth to reduce unnecessary variations in temperature.

What if my temperature data looks noisy?

Daysy is designed to deal with noisy measurements, and this leads simply to more yellow days. There are things that you can do to influence your measurements:

  • When you measure. Measure when you first wake up in the morning, and before getting out of bed. The more regular the amount of sleep you’ve had beforehand (with a minimum of 4 hrs) the better.
  • What you wear to bed. If you change from wearing wool pajamas to a silk nightgown your body temperature changes accordingly, albeit slightly. If you do this on a frequent basis, it looks like noise to daysy.
  • Your bedroom temperature. Generally, your bedroom stays the same temperature and so does your body. Similar to what you wear, the temperature of your bedroom and the thickness of your sheets have an influence on your body temperature as you sleep.
  • Where you measure. Try to measure in the same part of your mouth every day. The best place is the fleshy part at the bottom of your mouth, with a light amount of pressure. Avoid moving daysy around in your mouth as you measure (we’ve done it in the lab, and can see the temperature go up and down). Daysy is designed to reject measurements that are too noisy, and will grumble-buzz to ask you to try again.

Can I also use a different cable to attach daysy to the App?

Daysy comes with a 3.5 mm TRRS Audio Cable. Please use only this cable to connect daysy to your iPhone.

Daysy did not take my temperature. What do I do?

Please make sure the cable is not plugged into daysy and try to measure again. Be sure that the tip of the sensor is fully under your tongue to the right or left of the frenulum and your lips are sealed around the neck of the sensor.

Can my measurements get lost?

No. Daysy permanently stores all of your data in the device’s memory. If you sync it with daysyView, you also have the ability to store the data online in case daysy gets lost or stolen. If this happens, please contact customer support for what to do next.

How long does the battery last?

The battery lasts approximately 2 years. If the battery is nearly empty, daysy’s activation ring will blink frantically. Please change your battery as soon as possible.

How long is daysy under warranty?

Daysy has a 2 year manufacturer’s warranty. A description of the warranty was included with the device.

What battery do I need? And where can I buy it?

You need a coin cell battery (CR2032). You can buy one at most convenience stores.

Can I have too large of a temperature step?

Not really. Generally, women have a temperature step of around 0.3C. If you have a step of more than 0.5C, then something might have happened during the measurement process. Please contact support for a more detailed assessment.

The activation ring no longer lights up. What should I do?

Daysy's battery is dead and must be replaced.

My daysy was dropped. What do I do?

If your daysy is unresponsive, please contact your local support team.

I can't open the battery cover.

Please use a coin and turn the battery cover counter-clockwise to open the battery cover.

The synchronization to DaysyView does not work. What do I do?

Completely close the DaysyView App. Let Daysy fall asleep. Start DaysyView and wait for the calendar view to start. Plug Daysy in using the supplied cable. Wait for Daysy to wake up. If Daysy still doesn’t wake up by herself, do so by gently pressing the activation button once.

I lost my cap. Where can I get a new one?

You can order a new cap from your local distributor.

How can I clean Daysy?

Please clean Daysy with a damp cloth when needed. Don't soak Daysy in water because she is not waterproof.

My sensor is broken. What do I do?

Please call your local distributor’s customer service.

Questions about daysyView

Do I have to download the App to use daysy?

No. You can use daysy without using the App.

What is daysyView?

This is daysy’s App which you can download from the Apple App store. With daysyView you obtain additional information about your menstrual cycle.

DaysyView can be used with or without daysy. Without daysy, the App allows you to record and visualize your daily BBT measurements, and functions as a preview to the full App.

When paired with daysy, daysyView enables you to view your previous, current, and estimated fertility status after the data is synchronized with daysy, but remember, the most accurate information for today is always found on daysy herself.

DaysyView allows you to safely and securely store the data from daysy online enabling you to leave daysy at home, and still have access to the fertility status throughout the day. In addition, if your daysy gets lost or stolen, the online data can be used by technical support to restore your new daysy without losing a step.

Can I change my period on daysyView?

Please always enter your menstruation on daysy. If you made a mistake while entering your menstruation on daysy, you can change it with daysyView. You can only correct your menstruation for the last 3 days. To change menstruation, please go to the calendar view on daysyView, choose the day you want to update and edit the entry. You can enable/disable the menstruation for that day.

As soon as you do this, all days thereafter will switch to an estimated representation. Please connect daysy, and allow her to synchronize. Menstruation is a key parameter for the algorithm, so some days should be expected to change if you adjust this value.

Can I enter past menstruation data?

No. Daysy needs to learn your cycle from the beginning on as it is. Menstruation data can be changed on daysyView for the past 3 days, if necessary. Please note that on daysy herself you can only enter or change your menstruation data on the same day.

How do I understand the calendar in daysyView?

Fertility status is shown through colors. The colors on DaysyView match those seen on Daysy. With DaysyView you can see both the measured and the estimated future fertility status.

Solid-colored days, are days that have already passed. Days that are hollow, are estimated prognoses.

DaysyView uses dots to indicate additional information for a given day. If there is a dot on a green day, then it means either that menstruation has been entered for that day (for a filled-in circle) or that it is estimated to happen in the future (for a hollow circle). Similarly, a dot on a red day means that the day is an ovulation day.

Note: At the end of your cycle, Daysy reviews all the information for the previous month, and may update your ovulation day. You will not see the ovulation day appear on DaysyView until after your current cycle has been completed and you have started the next. Thus, you may see a different day appear on the app than the original day Daysy had shown your estimated ovulation day by a blinking red light.

I would like to import my data from other apps. Can I do that?

If using daysyView without a paired daysy, you can manually input your temperature data. When paired with daysy, you cannot.

The temperature measurements of daysy are more sensitive than normal thermometers. Therefore you cannot use old temperature data because we don’t want to risk using less accurate information and causing problems with daysy.

The data on DaysyView is different from the data on Daysy. What do I do?

This can happen if you haven’t synchronized Daysy yet today. Please connect Daysy to your phone, allow them to synchronize, and the two will agree.

What devices are compatible with DaysyView?

You can download DaysyView from the Apple iTunes Store onto your iPhone, iPad or iPod touch if it is iOS 7 or 8 compatible. You can also download DaysyView for Android in Google Play.

Is DaysyView available for Android?

Yes. You can download it from Google Play.

I would like an expert opinion.

In the answers section, you can click on the ‘Ask an Expert’ button. This brings up an email for direct contact with our support team. In order for them to be able to access your fertility data and answer your questions, you’ll need to enable “store data online” in the settings menu prior to sending the “ask an expert” email.

You may be asked by the support team to send your data (.csv) file. Please go to the send button (the box with an arrow pointing upward) and address the mail to your local support team. For Switzerland: For the US and Canada: For Europe and the rest of the world:

The .csv file with your data will be loaded and you can simply type an email with your question.

I love the messages to my partner. How can I get more?

These messages will be periodically updated with new versions of DaysyView. If you have any suggestions that you would like to make, please feel free to let us know.

How do I synchronize Daysy with DaysyView?

Simply connect Daysy with your iPhone or Android using the supplied cable and wake Daysy up by clicking on Daysy's button. As soon as DaysyView detects Daysy, your data will be automatically synchronized. It’s as simple as that.

The more often you synchronize, the less time it will take.

How do I change my name or e-mail address?

Your account is associated with Daysy’s serial number. Please go to Settings->User Details to change your contact information. If you are changing devices and want to keep the same account information, please contact support before connecting the new device to update your account.

What data can I enter in the App?

If you are using DaysyView without a Daysy, you can manually enter temperature readings. If you have a paired Daysy, you cannot manually enter temperature values as Daysy will do this automatically when you sync. Menstruation data for the past 3 days may be entered or corrected in DaysyView. It is recommended to sync Daysy immediately after changing menstruation data.

Questions about my cycle

What happens if my cycle is longer/shorter than normal?

Some amount of fluctuation in your cycle is normal and to be expected. Most users will have an ovulation day fluctuation of 1-3 days in the statistics view. Daysy uses this in the algorithm to create a high-confidence region to be certain that green days are really infertile days.

A higher ovulation day fluctuation means that daysy needs to use more yellow days to be confident of where you are in your cycle.

If you look in the statistics view and see that the ovulation fluctuation is more than 4, then please contact support to look at your cycle. Our support personnel can help you determine if this is an anomaly and give you tips on how to proceed.

My cycles are irregular. Can I use daysy anyway?

Yes. Daysy is designed to handle cycles of varying lengths without posing a safety risk. Nevertheless, extreme fluctuations might make using the device a little inefficient because it will result in a greatly increased number of "yellow" days. Fluctuations of several days are no problem at all.

If you normally have a regular cycle, but had a short period with more fluctuations, daysy will function with this well. If you have a large period of fluctuations that has passed, it may be advisable to reset daysy so that she can more quickly track your current, more-regular cycle. Please contact support if you would like more information.

However, if some of your cycles are as long as several months, we recommend using natural cycle regulators (herbal preparations). Please consult your gynecologist for more information.

My cycle fluctuates greatly. What can I do?

Vitamin B6 is known to help regulate the hormones associated with the female cycle. An herbal supplement know as Monk's pepper (Vitex) is also known to help regulate hormones and therefore even out the cycle. * Always consult your physician prior to beginning new vitamins or supplements.

Important vitamins to increase fertility.

Vitamins play an important role in promoting fertility. Vitamin B6 promotes conception, while Vitamin E may increase fruitfulness. Vitamin A promotes the construction of the mucous membranes in the womb, as well as in the vagina. This is important for the implantation of the fertilized egg. A deficiency can cause departure of the fertilized egg.

What should I do if I don't get my period?

Please consult with your doctor.

Your menstrual cycle

You are unique, so no woman is like another. Daysy honors your individuality by tracking and learning your individual cycle.

What are some estrogen rich foods?

Soy, flax seed, asparagus, oat flakes, garlic.

Will dieting affect my cycle?

Moderate dieting should not affect your cycle. However, extreme dieting may suppress ovulation and therefore cause your cycles to be irregular.

How does the "morning after pill" affect my cycle?

This varies from woman to woman. It also depends on where you were in relation to ovulation when you took the pill. The "morning after pill" may prevent ovulation, therefore your cycle will be different and Daysy will not be able to confirm ovulation and return to infertile days. It is also possible that the "morning after pill" will not affect the ovulation and your cycle will continue as normal. If you have bleeding prior to when you would normally have your menstruation, please do not enter this as a menstruation on Daysy or in daysyView. For detailed information, please give us a call.

I will be entering menopause soon. Is it still wise to start using Daysy?

Yes, Daysy is still reliable during this transition. Occasional delays in ovulation or failure to ovulate will cause Daysy to show "yellow." In fact, this helps women to see how their cycles are changing. Even financially, purchasing a daysy will pay off for you. Since our products are extremely durable, you can easily sell Daysy to someone else once you don't need it anymore.

Can I use Daysy while breastfeeding? What if my cycle hasn’t returned?

You may begin using Daysy as early as 6 weeks postpartum. At first your basal temperatures are showing a typical zig-zag pattern. Daysy will indicate yellow, meaning potentially fertile during this phase. A few days before the first ovulation, temperatures drop forming kind of a valley for about 6 days before the typical temperature jump indicating ovulation. On all postpartum cycles we analyzed so far, Daysy indicated this ovulation correctly showing green after 4-5 days of significantly higher readings just like it is to be expected under the strict rules of temperature analysis by Döring or Sensiplan. We recommend women postpartum (still breastfeeding or not) use barrier methods until the first green days indicated by daysy. From there on, most cycles will be relatively normal and return to the typical green, red, green pattern of fertility indication. Only women already familiar with the Billings method may want to use the analysis of mucus to narrow down the possible infertile days during the "yellow" phase. However, the pearl index of this method is lower than Daysy’s so we do not recommend it if the avoidance of a pregnancy has top priority.

How do I use daysy?

How soon can I rely on the fertility display?

You can rely on the fertility display from day one. Daysy is more cautious at the beginning, meaning more yellow days. As daysy gets to know you and your body, these will gradually decrease. The more regularly you measure (and keep measuring) the better.

Where do I measure the temperature?

Under the tongue, and with your mouth closed.

When can I start using daysy?

Right after you receive the device. However, if you have just stopped taking hormonal contraception, we recommend that you wait until after you had your withdrawal bleeding and then start measuring with daysy. Do not enter the first bleeding as menstruation into daysy. This is not a real menstruation, but a hormonal withdrawal bleeding. Maximum safety will always be provided.

Can I measure multiple times a day?

Daysy will only store the first measurement taken each day. If you are not sure whether you’ve taken your temperature or heard the beep-beep after the measurement, repeat the measurement again while you are still in bed. Daysy will allow you to measure again, but if a temperature was already recorded, it will not record the next measurement.

How can I check my fertility status later in the day?

Press the activation button on daysy and your fertility status will display.

I have missed some measurements. What shall I do?

Missing one or two measurements is not a problem; daysy’s program is able to use its knowledge of the female cycle and your past data to calculate your fertility for the day. However, missing multiple readings per cycle will result in a greater number of red or yellow days.

I want to start using daysy after pregnancy. What do I need to do?

After a pregnancy we strongly recommend that you delete all stored data by resetting your daysy because your menstruation cycle is likely to be different. Note that you can use daysy while you are breastfeeding, but it cannot predict the first ovulation and will give yellow days until ovulation has been confirmed. We highly recommend the use of a barrier method during this time.

I sleep at rather irregular intervals (shift work, getting up at night, sleeping in on weekends etc.). Can I use daysy anyway?

Yes, in fact daysy was designed especially for that type of woman. Simply take your temperature as soon as you wake up for the day. Daysy will only allow you to record your temperature once in an 18 hour period, thus ensuring that you do not duplicate your readings.

I have a baby, which means I have to wake up often during the night. Can I use daysy anyway?

Yes. The basic rule is that a woman should have had at least four continuous hours of sleep before taking her basal temperature. However, each woman reaches her resting body temperature at different times. If you have not been able to get 4 consecutive hours, but wake up feeling well rested, you are ok to take your temperature. If you have some nights that you just don’t get good sleep it’s ok. Daysy was designed to make up for omitted readings automatically, as long as omitting isn't the rule.

I had a sleepless night. Can I rely on the device anyway?

Yes. If your reading is influenced by a bad night or by drinking large amounts of alcohol (omitting a reading once in a while isn't a problem), this doesn't mean that the indicator becomes unreliable. Depending on the phase of your cycle, daysy will react accordingly. Either the reading will be recognized and ignored as an exception, or the device will show a yellow or red light for that day to be on the safe side. However, if you drank large amounts of alcohol the previous night, it is best to omit the reading as alcohol influences your BBT.

Do I have to do anything special when traveling? What if I cross time zones?

You can use daysy when traveling near or far. Generally, you will not need to do anything to daysy. She will be ready the next morning.

When traveling overnight or to a different time zone, skip the measurement on the morning of your arrival and measure the following day as usual. Make sure you have at least 4 hours of sleep in a row for an accurate measurement. When traveling back, simply repeat the process.

Can I share daysy with a friend?

No. Daysy is your very own fertility computer. If you want to give your daysy to a friend, you must first delete all of your data.

How do I take the best measurements?

  1. As soon as you wake up and before you get up: take Daysy and briefly press the activation button. The activation ring lights up briefly, and the fertility status of the previous day will illuminate.
  2. Press the button a second time and the activation ring rotates in a clockwise direction. The measurement can begin.
  3. Place the sensor under your tongue and close your mouth. The measurement takes approximately 1 minute.
  4. "beep" indicates the end of measurement.
  5. Daysy displays your fertility status valid for the next 18 hours.

How long does it take to record my temperature.

It will take approximately 1 minute to measure, record, analyze and display your calculated fertility.

How can I turn Daysy off?

Daysy will turn off automatically after 60 seconds of no use.

What should I do if my husband or my child measured with Daysy? Can I delete individual measurements?

Individual measurements can not be deleted. If you've measured first thing in the morning, then any other measurements will not be recorded and used to calculate fertility.

Do I have to take my temperature at the same time every day?

It is important that you measure right after waking up, before getting up, but it doesn't matter what time of day it is. The more regularly you measure, the more green days Daysy will be able to give.

Can I have intercourse before measuring?

No. You should take your temperature as soon as you wake up, prior to any physical activity. If you forget, simply skip your measurement for the day. Daysy will use her knowledge of your cycle as well as statistical data to calculate your fertility for the day.

I incorrectly entered my menstruation. How do I change this?

You can deactivate the menstruation for today by pressing the activation button until the purple light begins to blink again. If you incorrectly entered your menstruation in the last 3 days, go to DaysyView and update your entry there. You can only edit your menstruation data for the last 3 days. Therefore, please always just enter menstruation when you have it for as long as you have it on Daysy.

How do I know when I will be fertile?

The best way is always to look at Daysy in the morning, after taking your temperature. A fertile day is indicated by the red light. DaysyView can also show you estimates for the future to help with planning.

How do I get more green days?

The first step to making sure you get your maximum number of green lights is to take your temperature every morning as soon as you wake up, and before getting out of bed. The more days you miss a temperature reading, the less green lights you will receive.

A higher ovulation range will result in more red days so being sure that your body has the necessary vitamins and nutrients is essential. Supplements such as Vitamin B6 and Vitex (monk’s pepper) help to regulate hormones and therefore ovulation. * Always consult your physician prior to beginning new vitamins or supplements.

High mental and physical stress are also contributing factors to decreased green days. Training for a marathon or working out excessively may delay or even cancel ovulation, resulting in a higher number of red or yellow days. To relieve mental stress, try to take a few minutes each day to do yoga, meditate, or just read a book, whatever works for you.

How do I enter menstruation?

After you take your temperature and while Daysy is still awake, press and hold the activation button until the violet light remains illuminated. If you find it difficult to enter menstruation you can also put the synchronization cable into Daysy and activate menstruation while the cable is plugged in.

Can I set an alarm with Daysy?

You cannot set an alarm on daysy. You can set an alarm via DaysyView on your iPhone device.

When can I take my first measurement?

You can begin immediately. You do not have to wait for your first menstruation. However, if you have been using a hormonal contraceptive, you must stop these before starting the measurement and wait for your first proper bleeding. The first proper bleeding is not the pills-related bleeding, but the subsequent menstruation.

General questions about daysy

How does daysy work?

Daysy works by tracking your daily basal body temperature and menstruations. With just a few easy steps, daysy will calculate your fertility each day allowing you to plan or prevent pregnancy.

  1. Take your temperature as soon as you wake, before getting out of bed.
  2. Press and hold the activation button to confirm menstruation on the days you are having your period.
  3. daysy displays your fertility status valid for the next 18 hours.
  4. You can sync daysy with your daysyView App to view detailed information about your cycle.

I just came off birth control. When can I start using daysy?

Please wait until after you had your withdrawal bleeding and then start measuring with daysy. Do not enter the first bleeding as menstruation into Daysy. This is not a real menstruation, but a hormonal withdrawal bleeding.

Why is the method based exclusively on measuring the temperature?

Studies comparing users who monitor just their temperature with other users using additional information, such as mucus or intermenstrual pain, did not provide any advantage. These other methods were sometimes found to produce more insecurity and in some cases even reduced contraceptive safety. In addition, those studies did not show a difference between women experienced in natural family planning and those who had never learned about it. That's why the developers decided not to consider any additional features. In fact, the product's unique reliability of 99.3% can hardly be exceeded.

Does daysy come with everything I need?

Yes. You can start using daysy right after unpacking it. All that is needed is the insertion of the included battery.

When can I start relying on the infertile indicator?

As early as the first day of application.

Will the fertility indication also be correct if I take medication?

This depends on whether you just take a regular painkiller once in a while - that's no problem at all - or whether you take a medicine over an extended period of time. If that is the case, you should ask your doctor or pharmacist if your medication has an impact on your body temperature and therefore your cycle. If so, you should stop taking your temperature during that time; otherwise you can continue measuring as usual.

How often should I measure?

As often as possible!

After looking at all of our data archives, we found a definite relationship between how often users measure and how many green days they get. Simply put, the more often you measure, the better.

We define a ‘good’ user as anyone who misses less than 10 percent of the measurements. That’s roughly 2-3 days per 28 day cycle.

How can I get an expert opinion on my cycle information?

In the answers section, you can click on the ‘Ask an Expert’ button. This allows directly contact our support team. In order for them to be able to help you assess your fertility data and answer your questions, you’ll need to enable the option to share your data with us. Once you do this, the fertility data will be automatically uploaded and you can simply type an e-mail with your question.

Does illness reduce the fertility computer's reliability?

No. An increased temperature due to some illness will cause daysy to skip the day’s temperature measurement. Daysy will not include this false reading into its calculation.

What happens if I omit a few readings?

Not much. Based on the information stored internally, daysy can make up reliably for missing measurements. Although we do encourage you to take your temperature regularly in order to determine your fertile period as precisely as possible, omitting some readings does not reduce the product's safety. If you need to omit some measurements due to illness, daysy will soon return to normal afterwards.

Is Daysy as secure as the pill?

With a Pearl index of 0.7, Daysy is as safe as the pill on 'green' days. The safety of the algorithm Daysy uses to calculate your fertility has been confirmed by a number of independent studies. Most importantly: The Pearl index is not a hypothetical assumption, but rather a result of multiple - independent of the manufacturer - studies. The most extensive of these studies was carried out by the University Hospital Düsseldorf, with more than 650 women.

Is Daysy certified?

Yes, Daysy has CE certification and is registered as a class I medical device. Daysy is a Class I exempted device with FDA.

Can daysy only be used with the iPhone and with Android?

Yes Daysy can be used with the iPhone and with Android phones.

What is the Pearl Index?

The Pearl Index indicates the reliability of a contraceptive method. If 100 women use the contraceptive method X for a period of one year and one of them becomes pregnant despite correct use, X has a methodical Pearl Index by 1. It is important not to confuse the methodical Pearl Index with the application Pearl Index. The methodical Pearl Index indicates how reliable a specific method is, if it is used correctly, while the application Pearl Index indicates the number of unwanted pregnancies as a result of disregard for the regulations. For Daysy, this would be the case if pregnancy resulted from sexual intercourse on days the unit shows a red light. This is the reason why there are different Pearl Index values for the same method. Daysy has the methodical Pearl Index as follows: If the display of the device are properly followed, Daysy has an excellent Pearl Index of 0.7. This value is located in the same order of magnitude as hormonal methods of contraception.

How long does shipping take?

In general, your Daysy will arrive within 2-4 days.

How safe is Daysy?

With a Pearl Index of 0.7, Daysy is as safe as the pill on 'green' days. The safety of the algorithm Daysy uses to calculate your fertility has been confirmed by a number of independent studies. Most importantly: The Pearl Index is not a hypothetical assumption, but rather a result of multiple - independent of the manufacturer - studies. The most extensive of these studies was carried out by the University Hospital Düsseldorf, with more than 650 women.

How long is Daysy's warranty?

Daysy has a 2 year manufacturer's warranty.

I do high-performance sports. Do I need anything special?

High performance sports can affect the cycle and inhibit ovulation. However, natural contraception does not inhibit muscle development as does, for example, the pill. To see whether it affects your cycle, we can make an analysis of the cycle after you've measured a few months.

Does Daysy protect against sexually transmitted diseases?

Daysy does not protect against sexually transmitted diseases and therefore should only be used by those in a monogamous relationship. Condoms should always be used to protect against std’s.

I am not going to use Daysy anymore. What do I need to do?

If you plan not to use Daysy for an extended period of time, clean it, remove the battery and store it in a dry place. Your data will not be lost. If you want to continue using Daysy after pregnancy, you should however reset Daysy, as your cycle may have changed postpartum. Please check our video tutorials to see how you can permanently delete all data from Daysy. Should you simply want to take up measuring again after some time, without any additions to the family, Daysy may show only yellow until you confirmed your first period, as she cannot know where in your cycle she is, after the battery has been removed for some time. Once you confirmed your first period, she will then use your previously stored data to quickly show you green lights again.

How is fertility able to be calculated with just BBT?

Daysy works by measuring, recording and analyzing your basal body temperature. This is the temperature of your body at rest. Most scientific applications accept the body’s temperature immediately upon waking as a representation of the BBT.

There are 2 predominate hormones involved in the fertility cycle, estrogen and progesterone. Estrogen is dominant during the pre-ovulatory phase (follicular phase) of your cycle, the time from the start of your menstruation until just before ovulation. Immediately after ovulation, during the luteal phase, production of the hormone progesterone increases and remains at an elevated level until just before the next menstruation. Progesterone causes the basal body temperature to shift by approximately 0.2 degrees Celsius. Daysy uses a complex algorithm to determine the change in average temperature values between pre-ovulation and post-ovulation. When the change is recognized, your Daysy knows that ovulation has occurred and you are no longer fertile.

Initially, Daysy determines your fertile window based on statistical data. Statistically, women can ovulate as early as day 11, so Daysy begins the red days around day 6 or 7 depending on the length of your menstruation. The red days will continue until daysy has been able to confirm ovulation. In the beginning, Daysy is very cautious and it could take up to 5 or 6 days for Daysy to be certain that the temperature shift was in fact due to ovulation and not some other factor. Over the course of the first few cycles, as Daysy learns your unique fertility rhythm, it will slowly and cautiously reduce the number of red days. Daysy will begin to pinpoint your ovulation and start your fertile window (red days) to 5 days before your earliest ovulation. The fertile phase will then continue until ovulation has been confirmed.

How long does it take Daysy to reliably "learn" my cycle?

Generally, we say that the Daysy has a learning phase of 3 to 4 cycles. This does not mean, however, that you will not get any green lights (infertile days) during that time. Daysy will start out very conservatively and base your fertile window primarily on statistical data and statistically you could ovulate as early as day 11, causing Daysy to start your red (fertile) days around day 6 or 7 depending on how long your menstruation was. It will then stay red until ovulation has been confirmed, at which point it will change to green light indicating infertile. Over the course of the next several cycles, Daysy will begin to weigh your data more heavily against the statistical data and slowly narrow down and give less red days as it is able to pinpoint your individual fertile window.

Who developed Daysy?

Daysy was developed by Natalie Rechberg, CEO of Valley Electronics AG in Switzerland, and daughter of Dr. Hubertus Rechberg, creator of the world-known Lady-Comp. Daysy uses the same core technology and algorithms used by Lady-Comp, and adds its own personality with the use of DaysyView. Experience with the Lady-Comp family of fertility computers in practical use and their proven success in vivo have also made a considerable contribution. The electronic brain, containing knowledge about fertility, and other components are manufactured by leading suppliers from all over the globe. Daysy is a certified medical device after standard EN ISO 13485:2012.

When can I rely on Daysy?

From the very first day!

At what age can I begin using Daysy?

Generally, Daysy can be used once you get to a sexually mature age. Daysy does not protect against sexually transmitted diseases, so a condom should be used. Daysy needs consistent use to be effective.

Can I use Daysy if I smoke or drink alcohol?

Smoking should not affect the cycle or Daysy. High consumption of alcohol will affect the cycle! You should skip your next temperature recording after a night of drinking.

Why is daysy called daysy and not daisy?

Daysy comes from Day-Sy = daily synchronization. The name does not derive from the flower.

How daysy speaks to you

Daysy makes a sound. What does that mean?

Beep.-Beep. Daysy is happy with the result, measurement was successful. Beep. Entry of menstruation successful. Brrrrrrp (grumble buzz): Daysy is not happy. Measurement went wrong, self-test went wrong.

Why am I having so many yellow days?

For the first 3 months of use you will see a lot of yellow lights because daysy needs to learn your individual fertility rhythm.

The number of yellow days from Daysy can also be influenced by two major factors: how you measure and how your cycle changes.

If you think you have very noisy measurements, please see the FAQ item about noisy measurements.

The number of yellow days is also affected by changes in your cycle. Your cycle can be affected by a lot of different factors in your life such as:

  • higher than normal stress level (exams, wedding, moving, work, etc.)
  • changes in diet (starting a new diet, fasting, new foods in a new country, etc.)
  • changes in exercise routine (training for a marathon, etc.)
  • lack of sleep (a minimum of 4 hrs please)
  • travel

I heard a grumble buzz. What does that mean?

Daysy was unable to take your temperature. Please try again.

I heard 2 beeps. What does that mean?

Daysy successfully took your temperature.

The activation ring does not light up. What is wrong?

The battery is dead or not connecting properly and needs to be changed. When looking at the battery compartment, the connector on the right should lie below the battery to connect to the negative side and the connector on the left should be curved up and touching the side of the battery (positive). If adjusting or replacing the battery does not solve the problem, please contact our customer service.

All the lights take turns blinking. What does that mean?

Daysy is performing a self-test. It will be finished after 60 seconds and daysy will work normally after that.

Violet light is on. What does that mean?

This indicates confirmed menstruation. You entered menstruation.

What does the yellow light mean?

The yellow light indicates that Daysy needs more information about you. It also indicates if your cycle fluctuates. If you want to prevent pregnancy please see this light as red and use a barrier method during this time.

What does the red light mean?

The red light means you are in your fertile phase. During this time you can plan for a baby. If you dont want a baby please use other contraceptives such as:

Ceylor condoms Caya diaphragm Today Sponge

What does the green light mean?

That means you are in your infertile phase and you can enjoy your love life without other contraceptive measures. Please be aware that Daysy does not protect you against sexual transmitted diseases.

What does the blinking red light mean?

The flashing red light in a current cycle is just a prediction of ovulation. Generally, the longer you use your device, the more likely the predicted day of ovulation will correspond with the actual day of ovulation.

The violet light is blinking. What does that mean?

The purple light flashes when Daysy is waiting for your menstrual input. If you have menstruation, press and hold the activation button until the violet light remains illuminated. If you are not menstruating, press nothing and the violet light will continue to flash.