Relative fecundability of users and nonusers of contraception.

Abstract

Data from a fertility survey taken at the end of 1962 in Taichung Taiwan on 2443 married women (aged 20-39) were used to calculate the relative fecundability between birth control users and nonusers. The same women were interviewed at the end of 1963 and further follow-up was possible through a survey in 1965. 17% of the total accepted contraception; 78% of these selected the IUD and the rest used traditional methods. Using a Type I geometric model it was shown that acceptors who had used contraception had an initial fecundability about 25% higher than nonacceptors who had not used contraception prior to the interview which indicated that acceptors had had higher fecundability at marriage as well as at the time of the interview. These results suggest that family planning programs have a greater impact on fertility than would be expected if fecundability were the same for acceptors and nonacceptors. Approaching older women with higher parity who accept family planning methods more readily is important because of their greater potential in contributing to birth rates than other women in the same age groups.