Threshold Levels of Sperm Parameters Impacting on Pregnancy Rate in an Intrauterine Insemination Programme

Objectives. Intrauterine insemination (IUI) is frequently used as a first line strategy in the treatment of male and unexplained infertility. Threshold levels of sperm parameters associated with IUI success are controversial. The aim of this study was to evaluate the influence of sperm parameters on the outcome of IUI. Study Design. A prospective observational study. Patients and methods. This study included 295 IUI cycles. All IUI cycles were preceded by ovarian superovulation with clomiphene citrate 50 mg tablets orally twice daily for 5 days starting on the second day of menses and recombinant FSH 150 units IM on the 6th, 8th, and 10th day. Cycles were monitored by transvaginal ultrasound. The IUI was performed with a catheter 36 ± 4 hours after hCG injection. Sperm parameters before and after semen treatment for IUI were evaluated and correlated with pregnancy outcome. Results. A total of 29 clinical pregnancies were obtained, for a pregnancy rate per cycle of 9.83%. No pregnancy was obtained when less than one million spermatozoa were inseminated (p = 0.022). A statically significant increase in pregnancy rate was observed when normal sperm morphology was > 20% before semen treatment (p = 0.01) and> 25% after semen treatment (p = 0.034). NTSI (number of typical spermatozoa inseminated) and NTMSI (number of typical and mobile spermatozoa inseminated) significantly influence the clinical pregnancy rate. A 65% decrease in pregnancy rate was observed when the NTSI <2 106 compared to the NTSI ≥ 2 106 (5.16% vs 15%, p =0.004). Similarly, a 54% decrease in pregnancy rate was observed when the NTMS <106” compared to the NTMS ≥ 106 (6.12% vs 13.5%, p =0.026). Conclusion. IUI used for treating male factor infertility seems to have little chance of success when NMSI <1 × 106, NTSI < 2 million, NTMSI < 1 million. If theses thresholds cannot be obtained, IVF should be recommended.