UNEXPLAINED INFERTILITY

Unexplained infertility is a nebulous diagnosis that is justified only after a thorough and meticulous investigation of both partners. Even if the five basic tests constituting the infertility investigation hav e not revealed an abnormality, there may be a specific cause. Diagnosi ng unexplained infertility in this setting is somewhat arbitrary. In s uch couples, spontaneous pregnancies have been reported, with an avera ge cumulative pregnancy rate of 60% after three years. Some additional testing, however, is appropriate. Treatment of unexplained infertilit y, however, tends to be empiric if no cause is found. Our current ther apeutic plan entails superovulation with intrauterine insemination for at least four cycles. A cycle fecundity in the range of 0.23 may be e xpected but is highly influenced by the woman's age, with cycle fecund ity dropping to as low as 0.05 after age 40. Alternatives to superovul ation and intrauterine insemination are direct intraperitoneal injecti on of sperm with or without oocytes and intrafollicular injection of s perm. Gamete intrafallopian transfer and in vitro fertilization (IVF) are appropriate after a trial of empiric therapy. Our preference is to carry out IVF because the knowledge that fertilization has occurred i s important in that fertilization failure is a known cause of unexplai ned infertility.