Kambic R, Kambic M, Brixius A M, Miller S
Am J Public Health. 1981 Nov;71(11):1255-8. doi: 10.2105/ajph.71.11.1255.
A Natural Family Planning service was evaluated at the end of a 30-month developmental phase. There were 444 women taught and 322 method acceptor of which 248 intended to avoid pregnancy. NFP clients were older (mean age 26.9 vs 22.4 and 23.7 for comparison groups), and a larger percentage were married (83.1 per cent vs 23.0 per cent for the comparison group). After one year of use, the unplanned pregnancy rate was 14.4 per cent and the total dropout rate was 37.6 per cent by life table analysis.
在一个为期30个月的发展阶段结束时，对一项自然计划生育服务进行了评估。共有444名女性接受了培训，322名采用了该方法，其中248人打算避免怀孕。自然计划生育服务的对象年龄较大（平均年龄26.9岁，对照组分别为22.4岁和23.7岁），结婚比例更高（83.1%，对照组为23.0%）。通过寿命表分析，使用一年后，意外怀孕率为14.4%，总退出率为37.6%。
