3-6 months of treatment with Clomid pills (clomiphene citrate) might improve fertility by as much as 2 times as compared to no treatment. This is a very low level infertility treatment. Infertility specialists do not usually recommend Clomid treatment( without insemination) for unexplained infertility for women over the age of about 35. Most fertility specialists do not use it (without IUI) on any couples with unexplained infertility. If a woman is already having regular periods and ovulating one egg every month, giving Clomid, which will probably stimulate the ovaries to release 2 or 3 eggs per month (instead of one) is not really fixing anything that is broken - and is not likely to be successful.
Another major cause of infertility in women may be the inability to ovulate. Malformation of the eggs themselves may complicate conception. For example, polycystic ovarian syndrome is when the eggs only partially develop within the ovary and there is an excess of male hormones. Some women are infertile because their ovaries do not mature and release eggs. In this case synthetic FSH by injection or Clomid (Clomiphene citrate) via a pill can be given to stimulate follicles to mature in the ovaries.
A closer look at the data suggest that the benefit of letrozole over clomid depended on the BMI of the participants. For patients with a BMI of less than 30 kg/m2, the cumulative live birth rate was approximately 30% for each group. However, for patients with a BMI over 30 kg/m2, twice as many patients had a live birth in the letrozole group than the clomid group.
Only 30 percent of patients who receive 100 mg of Clomiphene a day will produce more than three follicles. Patients that produce less than than three follicles have about half the chance of getting pregnant than those that produce greater than three follicles. Patients that receive fertility medications but do not do an insemination have only half the success rates compared to those who do.