[Experiences with the sympto-thermal method of family planning]

Evaluation of 2,276 cycles in 439 patients who had been employing the double-check family planning method described by Thyma. The average length of the hyperthermic phase was 12 days. A tendency to longer hyperthermic phases was recorded in case of cycles of longer duration. In 74% of all cycles, the mucus peak was observed 1 to 3 days previous to the temperature rise. In 2,242 cycles, 3 pregnancies occurred which had not been planned, which corresponds to a Pearl index of 1.6. The temperature curves originally evaluated according to Thyma's criteria, were also assessed according to Roetzer's criteria. This analysis yielded 89.8% evaluable temperature curves according to Roetzer, in contrast to 77.8% evaluable curves according to Thyma. An additional disadvantage when using the "coverline" as suggested by Thyma, is the shortening of the post-ovulatory infertile phase which may occur occasionally.