Objective: To identify prognostic factors influencing the outcome of infertility treatment using homologous intrauterine inseminations (IUI-H).
Design: Retrospective study of all patients undergoing IUI-H at the Fertility Clinic, Odense University Hospital from August 1st, 1990 to July 31st, 1998.
Setting: University-affiliated infertility clinic.
Patients: Eight hundred and ninety-three couples undergoing 2473 IUI-H treatment cycles.
Main outcome measures: Infertility diagnosis, female age, number of follicles, type of hormonal treatment, length of follicular phase, endometrial pattern, 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 IUI-H cycle was 11.9% with a significant increase from 8.7% in 1990 to 14.8% in 1998. The multiple birth rate was 18.1%. The birth rate per couple was 27.2% after a mean of 2.8 treatment cycles. The pregnancy rate was highest in the first treatment cycle and the cumulative birth rate rose only slightly after the fourth treatment cycle. Of the main outcome measures the following were positively and significantly related to a successful outcome of IUI: i) The first treatment cycle - compared to the following up to six treatment cycles; ii) number of mature follicles up to five - at the time of insemination, however, with an unacceptable high rate of multiple pregnancies with more than 4 mature follicles; iii) use of CC/hMG-FSH as compared to CC only for ovarian stimulation; iv) number of motile sperms inseminated exceeding 5 million; v) time of insemination between the 13th and the 16th day in the cycle and vi) anovulatory or idiopathic infertility.
Conclusions: IUI-H is a simple and inexpensive treatment giving acceptable pregnancy rates for up to four treatment cycles providing that at least 3 to 4 mature follicles have developed at the time of insemination, which implies that hormonal ovarian stimulation and induction of ovulation is used, that insemination occurs between cycle day 13 and 16 and that at least 5 million motile sperms are available for insemination. Our results indicate that in the presence of tubal pathology or less than 5 million motile sperms, the couples should be referred directly to IVF-treatment.