Results of an efficacy-finding study (EFS) with the computer-thermometer Cyclotest 2 plus containing 207 cycles

Prospectively collected cycles of 207 women were used to find out the effic acy of the Cyclotest 2 plus algorithm in detecting the fertile time in a wo man's cycle. The results of the device were compared with the beginning and the end of the fertile time identified by the symptothermal method (STM) o f natural family planning (NFP). It was found that the algorithm led to dan gerous reduction of the fertile time (FT) in only 2 out of 207 woman cycles (0.96%). However, at the end of fertile time (FE) the device requested mor e abstinence than was necessary in about 12% of the cycles. We feel that mo re research should be performed on detecting the end of the fertile time.