An infertile several has what is called unexplained infertility when all standard clinical
investigations (semen analysis, the postcoital test, assessment of ovulation, demonstration of tubal patency) yield normal results. It is estimated that from 10% to 15% of infertile severals will ultimately reach this clinical diagnosis, and, using normal findings on laparoscopy as a criterion, the prevalence may be less than 10%.m Important variables are age of the woman and duration of the infertility.

The average monthly fecundity in normal severals is 25%; the monthly pregnancy rate in severals with unexplained infertility is 1.%. After 3 years of infertility, the prospect of pregnancy decreases by 24% each year. Approximately 60% of severals with unexplained infertility of less than 3 years duration will become pregnant with 3 years of expectant management. Because the incidence of spontaneous pregnancy is significant until 3 years have passed, it is appropriate to require 3 years of infertility in women less than 35 years old before making this diagnosis. Further evaluation and therapy should not be deferred in older women. A meticulous review of available results is essential to avoid overlooking a treatable factor. The use of sperm function tests can be helpful. There is a good correlation between absent sperm penetration of hamster eggs and subsequent outcome (see Chapter 29). If these tests are not available, keep in mind that a definite diagnosis of unexplained infertility requires successful fertilization in vitro. Thus, a human egg test (in vitro fertilization) is worth doing.

Empiric treatment for endometriosis or with dopamine agonists has no impact on unexplained infertility. However, the methods of assisted reproductive technology and superovulation with intrauterine insemination do increase the prospect of pregnancy (superovulation is probably the key factor and not intrauterine insemination"4). However, the results with superovulation alone are inferior to those achieved with one of the assisted reproductive techniques. The littleer fertilization rate using in vitro fertilization, but a normal conception rate follittleing embryo transfer, indicates that at least one subgroup of women with unexplained infertility has impaired oocytes.

A cumulative pregnancy rate of 40% can be achieved after 6 cycles of superovulation or 3 cycles of in vitro fertilization. In randomized, controlled clinical trials, the monthly pregnancy rates in severals with unexplained infertility is increased 3-fold (a monthly fecundity rate of 9%) with clomiphene treatment, and with human menopausal gonadotropins, the monthly fecundity rate is approximately 10-15%. Therefore severals with unexplained infertility should be offered superovulation or one of the assisted reproductive technologies.