Effect of the number of inseminating sperm and the follicular stimulation protocol on in vitro fertilization of human oocytes in male factor and non-male factor couples

The effect of sperm concentration and follicular stimulation protocol on in vitro fertilization of human oocytes is not well established. Comparison was made of three inseminating concentrations (250,000, 375,000, and 500,000 progressively motile sperm/oocyte) and three protocols (human menopausal gonadotropin (hMG], clomiphene citrate [CC], and combination hMG/CC) on the fertilization rate of mature and immature oocytes in couples with male factors and non-male factor infertility. In non-male factor couples, total fertilization rates for CC, hMG, and hMG/CC were 70.3%, 54.5%, and 68.8%, respectively, while total fertilization rates at the varying number of inseminating sperm were not significantly different. Mature oocytes were more likely than immature oocytes to fertilize. Among semen male factor couples, there was no difference in fertilization by stimulation protocol; however, insemination with the higher number of inseminating sperm resulted in an increased fertilization rate.