How safe is the symptothermal method
The symptothermal method is based on the examination of two or even three parameters: Temperature and cervical mucus or temperature and cervix, or all three. The different parameters complement each other and make the understanding of the cycle easier.
The Pearl Index is used, in order to determine the safety of family planning methods. The index shows how many out of 100 women fell pregnant (during the menstrual cycles experienced in 12 months, therefore 1,200 cycles) using a certain contraceptive.
The Pearl Index, can determine how safe a family planning method is, but only if the data was obtained from subjects using the method correctly (e.g.: the contraceptive pill was taken every day). Although it also can determine how safe the usage of a method is, taking into account data obtained from subjects that used the methods incorrectly (e.g.: the contraceptive pill was only taken on some days).
If the symptothermal method is used correctly, the pregnancy rate is extremely low. In fact, so far only three women fell pregnant after the 7,866 menstrual cycles that were monitored, as part of a study carried out by the University of Düsseldorf. This translates to a Pearl Index of 0.4, which is similar to the contraceptive pill.
If we take into account the cases, where the method has been used incorrectly, the symptothermal method achieves a Pearl Index of 2.3 (according to the University of Düsseldorf). Most pregnancies are due to unprotected sex during fertile days.
If during the fertile days, a couple has sex using a barrier device, such as a condom, the Pearl Index still is 0.4.
It is important to say, that the safety of the symptothermal method largely depends on the couple's motives and behaviour. It is vital, that both completely understand the method in order to know when the fertile days are, so necessary precautions can me taken (abstinence or usage of barrier devices, such as a condom).