Frequently, couples who do not conceive want to know when they should be concerned and what they can to improve their chances. Many studies have shown that for women who conceive and have a child, they do so with three to six months. So if you consider a group of women who have had children and query them on how long it took before they became pregnant, 85% will tell you they became pregnant within the first six months of trying to conceive. The other 15 % conceived sometime after the first six months. This study looked at all women, not just women who became pregnant. For this larger group of women, some will have a problem that will prevent them from ever becoming pregnant while others will become pregnant without any intervention.
A couple who has been trying for six months to a year might benefit from knowing if there is a problem that is reducing their chance of achieving a pregnancy, and if there is anything be done to correct it. For example, suppose a couple has moderate male factor (His sperm concentration is 5-15 million) and suppose they have been trying for a year. Her chance of achieving a pregnancy on her next cycle with intercourse, if she is 25, is not the 10% that the model predicts but is closer to 1%, considering the male factor. Given the knowledge that the couple has a male factor, they may want to choose therapy that could significantly improve those odds. IVF is not necessarily the next step, but IVF in a young woman with normal ovarian function albeit a husband with a moderate male factor, has approximately a 45-50% pregnancy rate for one cycle. This knowledge improves their chances roughly 49%!
There are two points to be made about computer models of success. First, these models do not assume that an infertility problem exists. Patients with certain problems will definitely not have as good a chance of conceiving as the model predicts. Therefore, it is important to screen for potential problems if a person has been trying to conceive for six months to a year.