Symptothermal method

The symptothermal method is a method of natural family planning (NFP). It helps to understand where exactly you are in your cycle, i.e. whether you can become pregnant or not. It involves observing various fertility indicators, such as core body temperature and cervical mucus. Certain calculation rules help to interpret these fertility indicators and to reliably evaluate the cycle.

The fact that cervical mucus and core body temperature are evaluated means that there is a “double check". This makes it possible to distinguish between fertile and infertile days much more precisely. The calculation rules of the symptothermal method have been researched and established by several studies (cf. studies by Freundl G, Frank-Hermann P, Gnoth C et al.).

What is the symptothermal method?

trackle supports you in the correct use of the so-called “symptothermal method. The trick is that NOT ONLY  the temperature but also other fertility paramerters are observed and included into the calculation- namely the “symptoms" of the “symptothermal method".


How does the symptothermal method work?

The symptothermal method is based on the interaction of the hormones estrogen, progesterone, LH and FSH with the body:

Before ovulation, your body is busy ripening several ovarian follicles. That's what the hormone FSH does. All of these growing follicles produce estrogen – and when enough estrogen is in the blood, the hormone LH becomes active and triggers ovulation: the best, most beautiful and most developed of the mature follicles, bursts and sends its egg cell on the journey.

While the egg cells is on the way, the follicle is closing. It become the yellow body of the ovary and produces progesterone. This hormone causes a characteristic increase in body temperature – this higher temperature persists until the next menstruation begins and a new cycle begins. The risen temperature remains until the next menstruation begins and a new cycle begins.

The symptothermal method uses the changes in cervical mucus and core body temperature to evaluate your cycle and to distinguish between fertile and infertile days. A rise in core body temperature is a sign for ovulation and that you are no longer fertile. If the cervical mucus gets clearer, more spinnable and transparent, you are close to ovulation and you are fertile. After ovulation, when the cervical mucus becomes thick, lumpy or disappears completely, it is a sign that ovulation has happened and you are no longer fertile.

How do I use the symptothermal method?

Every morning before you get up you take your temperature either orally or vaginally and note it down. Throughout the day you observe your cervical mucus and note its composition in the evening. Every evening you compare your temperature and the composition of your cervical mucus to find out whether you have ovulated or are about to ovulate.

According to the principles of the symptothermal method, ovulation has occurred when these two conditions are met:

1) A cervical mucus climax has taken place, in other words: cervical mucus of very good quality (particularly transparent, sticky and pullable) followed by three days of cervical mucus of clearly inferior quality.

2) A temperature peak has occurred, meaning that the temperature has been higher for at least three following days than the previous six days. The third higher temperature value must be at least 0.2°C higher than the one measured on the previous six days.

A slightly more complicated issue are the infertile days before ovulation. Here the cervical mucus plays an important role: it is a sign for the beginning of fertility. In addition, the last cycles are analysed and the temperature rise is used to calculate when the earliest ovulation happened. Again, the symptothermal method uses a “double check" to safely evaluate your cycle.

Abbreviations for cervical mucus and what they mean

To make the observation of the cervical mucus easier, the symptothermal method defines certain abbreviations, which we will explain to you briefly here.


dry; dry, rough, itchy uncomfortable feeling


cannot see anything, no cervical mucus at the vaginal entrance


felt nothing, no moisture, no sensation at the vaginal entrance


Appearance: cannot see anything, no cervical mucus at the vaginal entrance




cannot see anything, no cervical mucus at the vaginal entrance


wet or felt nothing


plump, whitish, cloudy, creamy, lumpy, yellowish, sticky, milky, not peelable; or tough


wet, slippery, slick, like oil, smooth


glassy, crystal clear, glassy translucent, like raw egg white (glassy interspersed with white threads), elastic or spinnable, stringy, liquid, reddish, reddish brown, yellowish-reddish

Advantages of the symptothermal method

Observing body symptoms, including temperature, has been proven to work. It is noninvasive, informative and helps women to get to know their body and make self-responsible decisions.

The symptothermal method and the trackle app help you calculate your fertile days by measuring your temperature and reliably evaluating the data.

Disadvantages of the symptothermal method

The interaction of the different hormones is a miracle – but also not a machine. Different things can bring the system out of balance.

And your everyday life is really packed? Measure, know and feel what your body is doing, while being busy – not so easy to implement.

That is why errors in the implementation of the symptothermal method easily occur – especially if it is measured selectively, i.e. only in the morning – and the data is entered or noted by hand.

Reliability of the symptothermal method

The symptothermal method, on which trackle is based, is well researched for many years, demonstrating its reliability in determining fertile days.

trackle makes the symptothermal method easy

To be able to realiably tell, when ovulation has occured and what the current cycle status is, temperature values must be properly measured, transmitted and combined with other body observations.

This is done by the trackle system for your:

  1. trackle only uses core body temperature from within your body – the so-called surface temperature, i.e. on the wrist, is too easy to influence
  2. trackle measures while you sleep. This avoids the error-prone selective measurement in the morning- this contributes to safety
  3. trackle transfers your temperature data automatically – no more mistakes, when entering curves, tables and apps
  4. trackle calculates your cycle according to the standards of the symptothermal method – well researched and reliable

Measure core body temperature accurately

The trackle sensor uses a high-precision thermometer that accurately records and stores your core body temperature ind hundredths of a second. This is in liene with the requirements of the symptothermal method.

While sleeping

The classic measuring in the moring is difficult: it requires a lot of discipline and a regular rhythm of life to be trule reliable. Measuring in sleep therefore makes your life easier: no matter when you wake up, when your are sleeping, whether, you are disturbed at night or have partied longer in the evening. By measuring your basal body temperature during sleep, the lowest value is definitely recognized. Certainly.

trackle does the work for You

Calculate, count, follow rules, enter values: yes, that is everything you need to do, so that the results are correct. But you do not have to do that yourself, right? There is the clever trackle system. It transfers your data and calculates everything that is necessary for a reliable result.

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Test trackle now and learn more about your fertility!

With trackle monitoring your cycle will be child's play. Due to the
precise temperature measurement and the sophisticated app you will
always know your cycle status and when you can get pregnant.