As a general rule, every method of cycle tracking has its justification and you should decide for yourself which method suits you best under your individual circumstances. Deviations between different methods can be caused by the type of method (e.g. early or late indicator), by physiological reasons of the user or by application errors.
Early or late indicator
The method of breathe ilo is based on the measurement of the CO2 partial pressure in a woman’s breath, which drops before ovulation. This makes breathe ilo an early indicator for the beginning of the fertile window and is based on an actual live measurement. Methods based on BBT (Body Basal Temperature) are a late indicator. The temperature rises from ovulation onwards and can therefore identify ovulation afterwards. However, the identification of the highly fertile days before ovulation cannot be done in real time with this method and can only be derived by estimation from past cycles. In addition, this only works for very regular cycles. Another common method is to measure the luteinizing hormone (LH) levels in a woman’s urine. The LH levels rise 24-48h before ovulation and thus enables it to be detected 1-2 days earlier, but reacts in a different way than breathe ilo.
Physiological reasons for discrepancies
Urine ovulation tests are not always conclusive. Diseases and medication, individually varying LH levels and the sensitivity of the respective test system influence the result. Individual LH levels in combination with varying sensitivity of the ovulation test used can be the reason why one test works well for some women and not for others. Sometimes it helps to test different providers at the same time. The timing of the test can also have a big impact on the result.
LH concentrations can fluctuate even during the course of the day. In addition, taking antibiotics, psychotropic drugs, hormone therapy or diseases of the liver, kidneys or ovaries can affect the safety of the ovulation test.
The temperature method requires accurate documentation of the basal body temperature over several cycles. The following factors need to be considered and carefully documented: Lack of sleep or change of sleeping patterns, stress, illness or similar, as these influence the basal body temperature.
In general, all methods have one thing in common. The rules of application must be followed very strictly for an accurate result. With breathe ilo it is particularly important to breathe calmly through the device as if you were breathing normally. (See also "The correct breathing into the breathe ilo device") Even though there is no dependence on the time of day, we recommend that you take the measurement as early as possible after getting up in the morning to ensure that it is as reproducible as possible.
Therefore, a possible variance does not have to be due to breathe ilo, as every method existing on the market has advantages and disadvantages. We advise you to choose the most suitable method for you to determine your fertility.