Natural family planning: suitability of the CUE method for defining the time of ovulation

The purpose of this study was to compare the CUE method for family planning with the Ovulation Detection Method for defining the fertile phase of the menstrual cycle. We evaluated 42 cycles from 10 women in Monterrey, Mexico, who were monitored by basal body temperatures, urinary LH, pelvic ultrasound, and the CUE monitor. The fertile phase of the cycle was adequately defined in all cycles using the CUE method, and in 35 cycles (83.3%) by the Ovulation Method. Using our protocol, the period of recommended abstinence with the CUE method is 9 days and with the Ovulation Method 11 days. The CUE method accurately defines the fertile phase of the menstrual cycle, thus improving the predictability of ovulation for women who use natural methods of birth control.