THE EFFECT OF VARYING INSEMINATING SPERM CONCENTRATION IN MALE FACTORAND NON-MALE FACTOR INFERTILITY DURING IN-VITRO FERTILIZATION

Objective - To assess the effect of varying inseminating sperm concent rations on fertilization rates and polyspermy in human in vitro fertil ization (IVF). Subjects and Methods - Eighty-six couples who completed 107 consecutive IVF cycles were assigned to one of three groups accor ding to the results of their semen analysis (SA), sperm penetration as say (SPA), and titers of antisperm antibodies (ASA). Group 1 (non-male factor) had normal results for SA, SI)A and ASA; group 2 had one abno rmal result; and group 3 had two or more abnormal results. Inseminatin g concentrations of 50,000, 250,000, or 500,000 progressively motile s perm/oocyte were prospectively assigned to groups 1, 2 and 3, respecti vely. Main Outcome Measures - Incidence of polyspermy and fertilizatio n rates. Results - A total of 992 oocytes were available for analysis. The fertilization rate of 61% for non-male factor patient (group 1) w as significantly higher than for male-factor patients [group 2 (48%) a nd group 3 (43%; P < .01)]. The incidence of polyspermy was 3.3%, 5.5% , and 0% for groups 1, 2 and 3, respectively, and did not differ signi ficantly between the non-male factor and male factor groups (P = .16). Polyspermic fertilization was increased in both mature (4.1%) and pos tmature (5.7%) as compared to immature oocytes (1.4%; P < .05). Conclu sion - In male factor infertile couples, increasing the inseminating c oncentration to 250,000 or 500,000 motile sperm/oocyte does not result in an increase in the incidence of polyspermy but does not improve fe rtilization rates.