This can be inferred by comparing the results of the following studies: the first series consisted of 100 fertile couples who conceived without timed intercourse and reported pregnancy rates of 50 percent at three months, 75 percent at six months, and over 90 percent at 12 months, whereas a second series of similar couples who used a method of fertility awareness with timed intercourse observed pregnancy rates of 76 percent at one month and 100 percent at seven months [2].