An automatic electronic device (Rite Time) to detect the onset of the infertile period by basal body temperature measurements

Two trials of an electronic thermometer (Rite Time), designed to record and interpret basal body temperature (BBT) patterns in normal ovulating women, are described. A total of 140 menstrual cycles from 34 women, who used the thermal or symptothermal methods of natural family planning, were studied. Rite Time gave a signal for the start of the infertile period in 117 cycles, of which 114 (97%) appeared to have occurred at appropriate times. Further studies using hormonal and ultrasound reference points for ovulation were carried out in 21 cycles. Rite Time generally produced BBT patterns of quality acceptable for interpretation of the periovulatory BBT shift. About one-half of the volunteers said that they would be willing to replace their conventional charting methods with Rite Time.