According to which rules does trackle evaluate?

The trackle cycle computer supports you in reliably evaluating your cycle and understanding whether you can get pregnant or not.

This evaluation is carried out using the symptothermal method, a highly reliable method of natural family planning (NFP).

With the Symptothermal Method (STM), fertility indicators such as core body temperature and cervical mucus are observed and evaluated using fixed calculation rules. With this evaluation of whether you are currently fertile or not, you can then safely prevent or fulfill your desire to have children.

The calculation rules of the symptothermal method, which trackle uses to evaluate your information, have been researched and defined by several studies (cf. studies by Freundl G, Frank-Hermann P, Gnoth C et al.).

Some of these rules are very complex, the user has to laboriously learn them and evaluate them manually on a daily cycle sheet.

The trackle cycle computer digitizes these rules and helps you to apply them safely and easily: based on your individual fertility indicators, i.e. the core body temperature and your cervical mucus observation, trackle applies the rules of the symptothermal method for you every day. In this way, errors in the evaluation of the user can be avoided and the application security of this contraceptive method can be increased.

If you still want to know which rules the trackle uses to evaluate your signs, you've come to the right place: On this page we explain the rules of the Symptothermal Method to you in detail.

Note: For the safe use of trackle it is not necessary to be able to apply all the rules of the STM manually. It is particularly important here that you follow the trackle instructions for use in order to ensure correct use. Above all, this includes the correct observation and entry of your symptothermal information in the app.

If you have any questions about usage or need help, you can contact our support at any time You will also find extensive knowledge about application, observation and evaluation on our website and our YouTube channel.

For comprehensive methodological knowledge, we also recommend the book: "Natural and safe - The practical book: family planning with Sensiplan".

Physiological basics

The Symptothermal Method helps to understand where you are in your cycle. Because your cycle status is the key information about whether you can currently get pregnant or not.

That is why we would like to briefly explain the most important characteristics of the female cycle to you. If you are interested in more detail about the interaction of your hormones during the different cycle phases, you will find it here further information.

Each cycle begins on the first day of menstruation and runs in two phases: The first phase begins with menstruation and ends with ovulation. The second phase of the cycle begins with ovulation and ends with the menstruation of the next cycle.

In each cycle, the fertile phase lasts a maximum of seven days. These seven days include both ovulation itself, during which the egg cell can be fertilized for around 12-18 hours, and up to five days beforehand, because sperm can survive in the female body for up to five days. This means that unprotected sex up to five days before ovulation and up to around two days after ovulation can lead to pregnancy, which means a total of around seven days per cycle.

However, ovulation by no means always takes place on the same day of the cycle, but sometimes earlier and sometimes later. In order to determine the fertile days as accurately as possible, ovulation must be found.

The changes in two body signs can be observed around ovulation: the appearance of cervical mucus and the change in core body temperature.

Overview of the rules

trackle evaluates the body signs according to the rules of the symptothermal method. It is initially assumed that each day is to be regarded as potentially fertile - unless a day may be released as infertile according to the rules of the STM.

Evaluation of the infertile phase before and after ovulation are based on different rules, which are explained below. Both are based on determining ovulation.

Rules for determining the infertile phase after ovulation

According to the rules of the symptothermal method, ovulation has taken place when these two conditions are met:

1. A cervical mucus peak has occurred

This means that the highest cervical mucus quality you have observed is followed by three days of significantly lower quality. To do this, the cervical mucus must be observed daily and entered into the app in the evening.

The highest quality does not always have to be S+: Cervical mucus of quality S or f can also represent the high point if three days of lower quality are observed.

The classification of the cervical mucus quality is based on the following classification:

  1. t: niedrigste Klassifizierung der Zervixschleimbeobachtung wird ausgewählt wenn:
      Empfinden: trocken, trockenes raues, juckendes, unangenehmes Gefühl UND
      Aussehen: nichts gesehen, kein Zervixschleim am Scheideneingang
  2. ∅ wird ausgewählt wenn:
      Empfinden: nichts gefühlt, keine Feuchtigkeit, keine Empfindung am Scheideneingang UND
      Aussehen: nichts gesehen, kein Zervixschleim am Scheideneingang
  3. f wird ausgewählt wenn:
      Empfinden: feucht ABER
      Aussehen: nichts gesehen, kein Zervixschleim am Scheideneingang
  4. S wird ausgewählt wenn:
      Empfinden: feucht oder nichts gefühlt UND
      Aussehen: dicklich, weißlich, trüb, cremig, klumpig, gelblich, klebrig, milchig, nicht ziehbar oder zäh
  5. S+ wird ausgewählt wenn:
      Empfinden: feucht, nass, schlüpfrig, rutschig, glitschig, wie eingeölt, glatt UND
      Aussehen: glasig, glasklar, glasig durchscheinend, wie rohes Eiweiß (glasig mit weißen Fäden durchsetzt), dehnbar oder spinnbar, fadenziehend, flüssig, so dünnflüssig, dass er “wegrinnt wie Wasser”, rötlich, rotbraun, gelblich-rötlich

You can find more information about cervical mucus and its properties here.

If the highest individually observed cervical mucus quality is reached again before the evaluation of the high temperature could be completed, the determination of the cervical mucus peak must be started from the beginning.

2. A rise in temperature has occurred

After ovulation, your core body temperature rises by approx. 0.2°C - this is referred to as a high temperature:

Basic rule of high temperatures

A rise in temperature has taken place when three consecutive measured values are higher than six previous measured values (see dashed auxiliary line). The third higher measurement must be at least 0.2 degrees higher than the highest measurement of the six previous lower values.

exception rule 1

If the third temperature value is not at least 0.2 degrees higher, a fourth value must be awaited. This must also be higher than the 6 previous, lower values, but no longer by at least 0.2 degrees.

exception rule 2

If after the first higher measurement the temperature in a day on or under falls below the value of the highest of the six previous values, you must also wait another day. If the temperature on this fourth day is at least 0.2°C above the highest of the six previous values, the temperature evaluation is considered complete.

Exception rules 1 and 2 may not be combined.

Release after completion of cervical mucus evaluation and temperature evaluation

On the evening of the last day on which both evaluations could be completed, infertility can be assumed for the cycle phase after ovulation.

In the trackle app, this happens at 7 p.m. according to UTC+1.

Rules for determining the infertile phase before ovulation

For the first phase of the cycle, the infertile period is determined according to the 5-day rule and the minus 8 rule.

The 5-day rule states that the first five days of the cycle can be considered infertile unless otherwise specified by the minus 8 rule.

The minus 8 rule states that the day of the cycle with the earliest first higher measurement minus 8 gives the number of infertile days of the first phase of the cycle. If less than 5 days come out after this rule, then the rule must be applied immediately. If more than 5 days result from this rule, the rule may only be applied if the user has been proven to have had at least 12 previous high temperatures.

disruptive factors

Disruptive factors can cause the basal body temperature to rise without ovulation having already taken place. Very important: Each of us is different and also reacts differently to stress etc. You can recognize a "disturbed" temperature reading by the fact that your temperature suddenly rises for a day or two and then falls again.

Common disruptive factors that affect basal body temperature in many women are:

- Drug consumption

– unusual consumption of alcohol

– short/disrupted night’s sleep

– Stress

– Time change

- Cold or illness, etc.

Entering a disruptive factor in the app means that this temperature value is ignored and not included in the evaluation of the cycle. So if there is a reason for the disruption and the temperature value shows an unusual increase, a disruptive factor must be selected in the app for the correct evaluation.
If a disruption reason has no effect on the temperature, no disruption factor is selected in the app.

Specific ads at trackle

Fertility status on the turquoise tab (home screen)

trackle updates the evaluation of your fertility every day, regardless of whether new temperatures or new observations have been added or not.
Why it is like that? The system updates your evaluations every day, even if no new entries have been made, because the mere passage of time without new observations causes changes. For example, if yesterday you were told that ovulation was predicted for tomorrow, this prediction will no longer be maintained today - either ovulation could be confirmed, then it will be displayed, or the prognosis could not be confirmed, then fertility will continue to be displayed .

Every entry regarding bleeding, cervical mucus and disturbances and every transmission of temperatures has an immediate effect on the evaluation. That's why the user has to check her current fertility status every day on the turquoise tab: only the information displayed there takes into account all available data and determines the current fertility.

Retrospective determination of ovulation in the calendar

When the evaluation of the cervical mucus peak and the high temperature have been completed and the remaining days of the cycle have been released as infertile, trackle retrospectively shows which days were actually fertile and on which day ovulation was most likely to have actually taken place.

The prognosis

The calendar shows an approximate prognosis a few days in advance of when the next ovulation could possibly start and when the next menstruation could possibly start. These forecasts only serve as a very rough guide for the user and must expressly not be used for contraceptive purposes. To decide whether unprotected sex is possible without becoming pregnant when using contraception today, the display on the turquoise tab must always be checked on a daily basis.