A prospective multicentre trial of the ovulation method of natural family planning. I. The teaching phase

The percentage of 869 women in five countries capable of being taught to recognize the periovulatory cervical mucus symptom of the fertile period was determined in a prospective multicentre trial of the ovulation method of natural family planning. The women were ovulating, of proven fertility, represented a spectrum of cultures and socioeconomic levels, and ranged from illiteracy to having postgraduate education. In the first of three standard teaching cycles, 93% recorded on interpretable ovulatory mucus pattern. Eighty-eight per cent of subjects successfully completed the teaching phase; 7% discontinued for reasons other than pregnancy, including 1.3% who failed to learn the method. Forty-five subjects (5%) became pregnant during the average 3.1-cycle teaching phase. The average number of days of abstinence required by the rules of the method was 17 in the third teaching cycle (58.2% of the average cycle length). To what extent the findings of this study can be extended to other couples remains to be demonstrated. A prospective multicenter study was conducted in 5 cities (Auckland, Bangalore, Dublin, Manilla, and San Miguel) to assess the teaching phase of a program on the ovulation method (OM) of natural family planning. 869 ovulating women of proven fertility representing a wide range of cultural, educational, and socioeconomic characteristics (83% Catholic) were taught to recognize the cervical mucus symptom of the fertile period and were then tested on the effectiveness of their learning. 52% of the subjects did not wish to have any more children. 93% were able to understand the method after 1 cycle and 97% after 3 cycles. In the 3rd cycle, the mean number of days of abstinence required was 17. 75.1% of the subjects entered the 2nd phase of the trial after the 1st 3 training cycles and an additional 8.3% after an extended period of up to 3 more cycles. 45 (5.2%) became pregnant during teaching and 99 (11.4%) withdrew from the study. 2, possibly 3, subjects became pregnant while following OM rules. 32 pregnancies occurred when couples had intercourse during the fertile period and 11 more resulted from inaccurate application of the instructions. Subjects who required teaching beyond the 1st 3 teaching cycles reported both pregnancy and discontinuation rates more than 4 times higher than women who did not require additional teaching.