The relationship of sperm parameters to cycle fecundity in superovulated women undergoing intrauterine insemination.

Semen parameters of raw and prepared (post-swim-up) specimens from 451 cycles of intrauterine insemination (IUI) were analyzed in relation to cycle fecundity in 232 patients undergoing ovarian stimulation with sequential clomiphene citrate/menotropin therapy. Pregnancy occurred in 42 cycles, resulting in an overall pregnancy rate of 17.7%, and a cycle fecundity of 9.3%. Cycle fecundity was positively correlated with the parameters of post-swim-up log sperm density (r = 0.994), and with log total motile sperm inseminated (r = 0.964; inseminates were limited to a maximum of 20 million total motile sperm). Post-swim-up motility did not correlate (r = 0.308) with cycle fecundity; however, most specimens had a motility of greater than 40% post-swim-up. Only one pregnancy occurred when less than 1 million motile sperm were inseminated (38 cycles), which resulted in a cycle fecundity of 2.6% for these cycles. This may represent the threshold of effectiveness for IUI in this setting. Highest cycle fecundity was obtained with an inseminate containing approximately 10 million or more motile sperm. Parameters of raw samples correlated less well with cycle fecundity than did prepared specimens. Analysis of post-swim-up semen parameters can provide useful prognostic information for women undergoing IUI with ovarian stimulation; this information is helpful in counseling patients regarding their chances of success with this therapy.