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How to Recognize Ovulation with Your Daysy Fertility Tracker

ovulatie berekenen, wanneer is mijn eisprong

You expect ovulation to occur midway through your cycle. We've all been taught that. But what if you sit and wait for ovulation but ovulation doesn't come yet? Very frustrating, you start doubting yourself "am I doing something wrong" or "is something with my body not OK"?

You see the 'expected ovulation' in the calendar in the DaysyDay app but suddenly it has disappeared again and you still have red days. How about that? Why does ovulation disappear? In this blog, I'm going to explain exactly how it is so you know if you have an ovulation and when it was. Are you not ovulating? Then be sure to start using the ti

The moment of ovulation

Ovulation is the moment in the menstrual cycle when you switch hormones. Before ovulation, everything is geared towards it. Your body produces estrogen for this, the hormone that thickens the cervical mucosa, among other things. After ovulation, the switch follows to the production of the hormone progesterone, which supports an eventual pregnancy.

ovulatie moment, ik voel wanneer mijn eisprong is

Ovulation affects your mood

Every month when the ovaries get ready to release an egg, they produce oestrogen. Estrogen, in turn, stimulates the neurotransmitter serotonin, which can make women more cheerful and energetic in the few days before ovulation. Oestrogen also positively affects your libido.

After ovulation, one of the ovaries releases a huge amount of progesterone. Progesterone is the calming, soothing, anti-inflammatory hormone that every woman can put to good use.

Ovaries make progesterone with the hormone-stimulating gland: the corpus luteum. The corpus luteum (yellow body) is what remains of the follicle that first contained the egg (see image above). The corpus luteum can produce enough progesterone if the nutrients were previously abundant for the follicle containing the egg.

Myths about ovulation: You only need an ovulation if you want to get pregnant.

This is incorrect: every woman needs the hormone progesterone (i.e. produced after ovulation), not only if you want to get and stay pregnant. Among other things, progesterone also ensures better bone density and thus more solid, strong bones. A study (1.) examining bone density in women using hormonal contraception found a decrease in bone density in the hip region compared to non-users.

What does science say

Scientists have discovered that in the corpus luteum after ovulation, a network of blood vessels is rapidly built by the M2 macrophages of our immune system. That network of blood vessels is needed so that the corpus luteum can make progesterone. (2).

The corpus luteum has a short lifespan (12-14 days). Therefore, it needs a vascularised structure (blood vessel network) of 4 cm quickly (within a day) so that the production of progesterone can start properly.

eierstokken, ontwikkeling van het eitje voor de ovulatie

M2 Macrophages are a type of white blood cells that have an important role within our innate immunity, our first line of defence against foreign invaders. Macrophages also secrete anti-inflammatory cytokines (small signalling proteins) and aid in repair processes. (3).

Nowhere else in the body do you create new tissue in such a short time that needs blood supply so quickly!

How do I boost my immune system?

So a well-functioning immune system also plays an important role for your cycle.

Therefore, advice to ensure a good basic foundation in terms of diet plus immune- and hormone-supporting supplements are recommended.

The rapid development of the corpus luteum requires nutrients such as cholesterol (good fats), B vitamins, coQ10, vitamin D, iodine, magnesium and zinc. This gland in particular has a high need for the antioxidant selenium, which is why selenium is the nutrient for progesterone. You know: the substance found in Brazil nuts!

Tip: eating 2-3 Brazil nuts a day already ensures that you get the RDA of selenium. However, never eat more than five Brazil nuts a day for long periods of time, as there is then a chance of getting too much selenium.

No ovulation

It is not uncommon to have an anovulatory cycle, a cycle without ovulation, once a year. We see more anovulatory cycles occurring these days because environmental factors such as diet but also toxic substances affect the functioning of the ovaries and thus can damage the capacity of our fertility.

Other causes for failure to ovulate include illness, travel/holidays, stress or not eating enough (calorie restriction, low-carbohydrate). If ovulation fails to occur once, there is no immediate cause for concern. But if you have 3 consecutive cycles with no temperature rise and thus no ovulation then your body needs extra support. In that case, ladies who measure with a Daysy or LadyComp see more than 10 red and yellow days per cycle.

But I do menstruate!

True, you get your period even if there has been no ovulation. What your body sheds during your period is built-up mucus, fluid and blood made by the hormone oestrogen on the inside against the uterine wall. You shed that regardless of whether there are remains of an egg with it.

Having regular cycles does not guarantee that you will also have ovulations.

You have no idea what happens between periods, which is precisely what is essential to know if you are fertile. Frustrating for many women, you assume that everything is OK but you can't manage to get pregnant, for example. Women have health problems for which the cause is easy to identify, also the solution is available. Suppose you had not ended up on our site what would your life have been like going forward?

Ok, are you ready? Let's dive in further.

What if you are not ovulating?

A short luteal phase (from ovulation to first day of next period) of less than 10 days or CLI (corpus luteum insufficiency), low or no rise in BBT indicate that there is a problem with ovulation and the corpus luteum, the progesterone production. Rapid decrease in progesterone if the corpus luteum does not work optimally and for long enough then you can nastily slip into PMS symptoms like irritability, depressed/nepressed, bloating, low energy and sensitive breasts. You may also experience painful, long periods and heavy bleeding. The list of possible complaints doesn't stop there, ladies!

Are you on the pill? Then you have no ovulation, no corpus luteum, no luteal phase and no progesterone. Further, hormonal contraception robs you of the calming, mood-enhancing effects of progesterone.

Help! I have a lot of red days with my Daysy

Apparently, your body is not yet ready for ovulation to take place. Then you will keep having red days because you are still in the fertile days before ovulation. Sperm can survive a maximum of 5 days internally before ovulation. Daysy remains safe!

Only after ovulation does your temperature rise slightly and you get green colors when your temperatures show a stable higher reading for a few days.

Picture below: overview measurements with the Daysy Cycle Tracker in the analysis report. No ovulation, no temperature rise, no green days before menstruation.

meet je cyclus, weet wanneer je vruchtbare en onvruchtbare dagen zijn, je kunt niet iedere dag van de maand zwanger raken

I feel my ovulation

Many women notice a pain sensation left or right in the lower abdomen and label this as the ovulation moment. This is possible, but you can also feel this while the follicle is not yet ready to actually open and release the egg. Ovulation pain is thus not a reliable symptom to determine the actual moment of ovulation.

Determining ovulation

The exact moment of ovulation can be observed with an internal ultrasound, but we are not going to lie in the doctor's chair for days on end waiting for it to happen. That is not feasible. Fortunately, it doesn't have to be because your BBT (basal body temperature) shows when ovulation was. Therefore, measure your resting temperature with the Daysy Cycle Tracker every morning as soon as you wake up before you get up and get active.

You will see all 3 ovulation analyses that your Daysy does, in the app after syncing.

The expected ovulation may disappear if your readings show that your ovulation has not yet occurred. Read more about how the smart internal algorithm in your Daysy does the ovulation calculation.

Is ovulation testing reliable?

We often hear that an ovulation test is positive but in reality ovulation is not taking place or not yet. It is known that an ovulation test can be positive at more times but that does not mean that ovulation actually occurs within a few days. That is what your body determines, only possible if the preparation towards ovulation has gone well.

The internal algorithm in the Daysy remains 99.4% accurate, it tracks your BBT (basal body temperature) and it rises slightly but only after ovulation, due to progesterone production which you have learnt by now. Hence, if you have no rise you know you skipped ovulation. You can just menstruate without having ovulated. How smart is measuring BBT? Essential, even for ladies with PCOS!

How do you recognise ovulation?

The smart internal Daysy algorithm performs three different calculations for ovulation.

verwachte ovulatie op basis van eerdere cycli

1st calculation - based on the average day of ovulation in previous cycles.

You have confirmed the menstrual days and you hit the expected ovulation in this cycle.

If your ovulation does not occur at the expected time, the 'expected ovulation' will disappear from the app. Do your colors remain red or yellow (fertile days) because you are still in the fertile days for ovulation.

Daysy remains accurate.

eisprong heeft nog niet plaatsgevonden, nog geen ovulatie

2nd calculation

The likely day of ovulation - based on the temperature shift in the current cycle.

Your temperatures have shown that you are past ovulation. Ovulation is displayed.

As a result, the internal algorithm in the Daysy learns from your body to indicate the next 'expected ovulation'.

moment van ovulatie, wanneer is mijn eisprong

3rd calculation

The calculated ovulation day - based on the analysis of the completed cycle (usually the same or very close to the 2nd calculation).

You are on day 5 of your next cycle. Daysy evaluates your entire previous cycle and posts the ovulation day. This information is also taken into account for subsequent cycles.

The ovulation day cannot be during higher temperatures because you only make the hormone progesterone after ovulation, not before it!

If a next cycle does go differently, Daysy will still give the accurate current information.

A quick note on how Daysy does the ovulation calculation

The predicted ovulation marker is shown from the beginning of the cycle until a persistent temperature shift is established. Once the persistent temperature shift is established, the ovulation marker is moved to the likely day of ovulation (still shown as predicted ovulation in the app text). Once the user is about 5 days into the new cycle, the ovulation marker moves to the calculated ovulation day and it reads "ovulation" in the app.

If no constant temperature shift has taken place within 5 days of the originally predicted 'expected ovulation' day, the predicted ovulation marker disappears from the app because it did not take place.

There will be no other ovulation indication in that cycle until a sustained temperature shift is detected and the 2nd calculation can be performed.

Daysy performs 3 moments of ovulation precision:

  1. The expected ovulation in advance visible in the app

  2. The ovulation itself

  3. The evaluation of the entire past cycle

How does the 3rd calculation work?

Daysy evaluates on day 5 of your next cycle the entire previous cycle and moves the ovulation marker to the calculated ovulation day.

When your new cycle starts, the ovulation marker from the previous cycle disappears for a few days while Daysy waits to see if the menstrual data is correct or removed. Once you are about 5 days into the new cycle, Daysy evaluates the previous cycle in its entirety and displays the calculated day of ovulation.

Daysy indicates the expected ovulation in subsequent cycles based on what it has seen from your body. If your cycle takes longer and you have many red days without seeing a temperature rise after which you would otherwise have green days, your ovulation has not occurred or has occurred late. It's possible!

So am I fertile?

Ovulation is obviously important for your fertility, that is the day you are fertile per cycle, but it is so much more than that. If you don't ovulate, no egg is released, you can't get pregnant. Ovulation is the only way to switch from oestradiol to progesterone. Hormones that are good for mood, energy, libido, insulin response, thyroid, skin, hair and much more.

A balanced cycle provides the essential ovulation. Is the basis for your health from puberty to menopause (and beyond)! Because building strong bones is what you need even when you're 72!

When does your temperature stay high and keep making progesterone?

Basal body temperature is a good way to observe pregnancy at a very early stage. If your period is delayed and your basal body temperature remains elevated for more than 18 days, Daysy may give the message 'possibly pregnant' and you can take a urine pregnancy test. It may be that your period is later without being pregnant then the urine pregnancy test is obviously negative.

kinderwens, Daysy de cyclus tracker geeft aan dat ik zwanger ben
zwangerschapshormoon, mijn menstruatie blijft uit, ben ik zwanger

innesteling van bevrucht eitje in de baarmoederwand, ik ben zwanger

positieve zwangerschapstest, hoera zwanger, kinderwens vervuld

innesteling van bevrucht eitje, Daysy cyclus tracker, hoe weet ik dat ik zwanger ben

Implantation of the fertilised egg

You may even observe a second rise in basal body temperature due to the implantation of the fertilised egg in the uterine wall.

Progesterone production continues to rise that allows you to stay pregnant. Implantation of the fertilised egg takes place about 6 -12 days after your ovulation.

Daysy is not a pregnancy test. Daysy is there to give you insight and tell you what you want to know.

Tips! To promote ovulation even if you have PCOS:


Even 2 glasses of alcohol a day can disrupt your hormone production!

Gut health

If your gut microbiome is not healthy, it negatively affects hormone production and the immune system. Therefore, maintain a healthy microbiome and support your gut if necessary with a good probiotic. Medicines, antibiotics, pro-inflammatory foods and stress disrupt your gut flora.


Plastic and pesticides disrupt your own hormone production. We run daily on our hormones, which determine how you are doing from head to toe.

Avoid pro-inflammatory foods like:

Sugar, grains, cow's milk products because they interfere with your own hormone production. These nutrients promote the production of histamine which goes hand in hand with more PMS symptoms and other hormonal disturbances.

There you will find detailed explanations and advice.

You generally recognise your health by a balanced cycle pattern.


Does your Daysy on day 5 of your current cycle indicate no ovulation day in the past cycle or do you have more than 10 red days per cycle month after month? Then you have a good reason to immediately start working on nutrition, lifestyle and supplementing with nutritional supplements. Above all, don't forget about reducing stress factors! Because stress from outside and/or inside your body is the most disruptive factor of your immune system.

The science is clear on the relationship between a healthy immune system and having or not having ovulations. Our natural immune system, through the M2 macrophages, provides an important role to enable the production of progesterone in the ovaries. Therefore, support your immune system with vitamins D3, B12, C, zinc, quercetin, magnesium, omega 3 oil and the adaptogenic herbs to balance your cycle.

cyclus plus pakket, hormonale balans

Compiled by orthomolecular therapist and fertility expert Patricia Dijkema.


  1. Studie: Combined hormonal contraceptives use and bone mineral density changes in adolescent and young women in a prospective population-based Canada-wide observational study

  2. ABC science. Infertility linked to missing immune cells. 3798293

  3. Macrophages what are they, different types, function, and more. Author:Lily Guo. Osmosis from Elsevier



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