RELATIONSHIP BETWEEN HUMAN IN-VITRO FERTILIZATION AND INTRACYTOPLASMIC SPERM INJECTION AND THE ZONA-FREE HAMSTER EGG PENETRATION TEST

The zona-free hamster egg penetration test (HEPT) is widely used for e valuating the fertilizing ability of human spermatozoa, However, the r elationship between the HEPT and microassisted fertilization has yet t o be determined. To evaluate the efficiency of HEPT in selecting the m ost appropriate method of in-vitro fertilization (IVF), including intr acytoplasmic sperm injection (ICSI) in couples with male factor infert ility, clinical laboratory data was analysed retrospectively. The pati ents were divided into groups according to the sperm penetration index as determined by the HEPT: group A (sperm penetration index = 0), gro up B (sperm penetration index <15) and group C (sperm penetration inde x greater than or equal to 15). A total of 405 oocytes were collected and inseminated by conventional methods in 69 couples with male factor infertility. In all, 31 out of 148 (20.9%) oocytes fertilized in grou p A; 35 out of 117 (29.9%) in group B; and 73 of 140 (52.1%) in group C, The clinical pregnancy rates per transfer in groups A, B and C were 0% (0/13), 0% (0/14) and 25.9% (7/27) respectively. Both the fertiliz ation rate and pregnancy rate in group C was significantly higher than in groups,4 and B, ICSI was carried out in a total of 57 couples and 334 oocytes in metaphase II stage mere manipulated. The normal fertili zation (2 pronuclear) rate per oocyte was 65.6 +/- 26.0 % (mean +/- SD ), Out of 127 oocytes, 76 (59.8 %) fertilized in group A, 57 out of 87 oocytes (65.5%) in group B and 86 out of 120 oocytes (71.7%) in group C, Of the 56 transfers, 17 clinical pregnancies were obtained, giving an average pregnancy rate of 30.4% per transfer. The clinical pregnan cy rates per transfer in groups A, B and C were 17.4% (4/23), 40.0% (4 /10) and 39.1% (9/23) respectively, No significant differences were ob served in the fertilization rates or in the pregnancy rates between th e three groups, In addition, there were no differences in the fertiliz ation and pregnancy rates between the ICSI and IVF patients in group C , These findings suggest that the results of the HEPT are well correla ted with the fertilizing ability of human spermatozoa in the patients treated by conventional IVF. Couples suffering from male factor infert ility with a sperm penetration index of <15 (as determined by HEPT) sh ould consider treatment with ICSI, while those with a sperm penetratio n index of greater than or equal to 15 should attempt conventional IVF .