[Prospective study of the efficacity of a recent symptomatic-thermal method of natural family planning]

A Belgian pilot-study conducted in the framework of the prospective European multi-center study (University of Düsseldorf) tried to establish the use-effectiveness (a sine qua non condition for its acceptance in Europe) of natural family planning.

84 participants provided data (sympto-thermal chart and related information) on 1,750 cycles where family planning intention was to avoid a pregnancy. The average age of the women was 32 years. A contraceptive method (mainly oral contraceptives) was employed previously by 61% of them. The sympto-thermal method used by the test group highlights the beginning and the end of the menstrual cycle's fertile period by a double check. As to the start of the fertile period, the criteria are: a calculation on the length of the previous twelve cycles and the first sign of mucus at either the vulva or the cervix. Indicators of the end of this phase are: the third day of high temperature and the fourth evening after either the peak mucus day or the peak cervix day. 75% of the women involved generally use the cervical auto-palpation.

No method failure at all has been detected. Two unplanned pregnancies occurred due to user failure. The total Pearl index for the study was 1.4. When examining only those cycles (85% of the reported cycles) where no protected sexual intercourse occurred during the fertile phase, practical efficacy of the method analysed was 1.8 according to Pearl index. Furthermore, taking into account protected and unprotected sexual intercourse occurred during the fertile phase, we observed that sexual abstinence was practised during the "risk" period of 75% of the cycles.

The results of this test study demonstrate the practical efficiency of a modern natural family planning method. The high level of cycles during which periodic abstinence was employed testify to the acceptability of the method used.