Intrauterine insemination with donor semen. An evaluation of prognostic factors based on a review of 1131 cycles

OBJECTIVE: To identify prognostic factors influencing the outcome of infertility treatment using intrauterine insemination with donor semen (IUI-D). DESIGN: Retrospective study of all patients undergoing IUI-D between August 1st, 1990 and July 31st, 1998. SETTING: University-affiliated infertility clinic. PATIENTS: Three hundred and five couples undergoing 1131 IUI-D treatment cycles. MAIN OUTCOME MEASURES: Type of hormonal treatment, number of follicles, length of follicular phase, endometrial pattern, female age, infertility diagnosis and semen quality related to clinical pregnancy rate, cumulative birth rate and multiple gestations. RESULTS: Throughout the nine year period the overall clinical pregnancy rate per cycle was 22.3%, with an increase from 12.9% in 1990 to 34.6% in 1998. The multiple birth rate was 20.6%. The birth rate per couple was 61.1% after a mean of 3.2 treatment cycles. The pregnancy rate was highest in the first treatment cycle and the cumulative birth rate rose only slightly after the sixth treatment cycle. The following parameters were positively and significantly correlated to a successful outcome of IUI-D: i) the first treatment cycle - compared to the following up to six treatment cycles; ii) number of mature follicles - more than one - at the time of insemination, however, with an unacceptable high rate of multiple pregnancies when more than 3 mature follicles were present; iii) time of insemination after the 12th day in the cycle; iv) insemination after ovulation has occurred and; v) female age under 30 years. CONCLUSIONS: IUI-D is a simple and inexpensive treatment giving acceptable pregnancy rates for up to six treatment cycles if at least 2 mature follicles have developed at the time of insemination, which implies that hormonal ovarian stimulation and induction of ovulation is used, and ovulation has occurred at the time of insemination, which ought to take place after cycle day (cd) 12 with at least two million motile spermatozoa.