Life-table analysis of artificial insemination pregnancy rates for couples with male factor and idiopathic infertility.

In the summer of 2002, standard guidelines for the application of assisted reproductive technology were reported by a research group of the Ministry of Health, Labor and Welfare. The present study aimed to examine the relationship between the number of cycles of artificial insemination and the cumulative pregnancy rates according to the cause of infertility. Patients who experienced their first cycle of artificial insemination during the period of January 1999-December 2002 were included in the study and were divided into a male factor infertility group and an idiopathic infertility group. Cumulative pregnancy rates resulting from artificial insemination with the husband's semen were calculated by the life-table approach. During the study period, 139 couples entered the assisted reproduction program and underwent 581 cycles. Significant differences were observed in cumulative pregnancy rates between the two groups. It is recommended that couples with male factor infertility and who fail to conceive within six or seven cycles of intrauterine insemination, consider a modification of treatment strategy such as fertilization, because cumulative pregnancy rates of this group were reached at a plateau within six or seven cycles. In contrast, patients with idiopathic infertility, the cumulative pregnancy rates appeared to increase constantly with each subsequent cycle. It is important to consider modifications of treatment strategy in the light of the cause of infertility. (Reprod Med Biol 2004; : 27-31).