Leridon H, Spira A
Fertil Steril. 1984 Apr;41(4):580-6. doi: 10.1016/s0015-0282(16)47781-2.
Couples consulting for infertility are a highly select group, and this makes the evaluation of the effectiveness of a type of therapy difficult. The most obvious selection results from the time they have been unsuccessfully waiting for a conception. Because fecundability is variable from one couple to another, the monthly probability of conceiving after 2 or 3 years of waiting time is low, but the proportion of couples who will conceive within 1 year is still significant and can be predicted. However, in most cases, couples submitted to a specific treatment include hypofertile and totally sterile couples, in unknown proportion. This fact makes difficult the measurement of the effectiveness of therapy, and procedures including control groups should be used. An example of such a process is given.
寻求不孕不育治疗的夫妇是一个高度特定的群体，这使得评估一种治疗方法的有效性变得困难。最明显的筛选因素来自于他们等待受孕失败的时间。由于不同夫妇的受孕能力各不相同，等待两三年后每月受孕的概率较低，但在一年内受孕的夫妇比例仍然可观且可以预测。然而，在大多数情况下，接受特定治疗的夫妇中，生育能力低下和完全不育的夫妇比例不明。这一事实使得衡量治疗效果变得困难，应该采用包括对照组在内的程序。文中给出了这样一个过程的示例。
