T. Ord

Penetration of zona-free hamster oocytes using human sperm aspirated from the epididymis of men with congenital absence of the vas deferens: comparison with human in vitro fertilization *

OBJECTIVES To assess the ability of sperm aspirated from the epididymis of men with congenital absence of the vas deferens to penetrate zona-free hamster oocytes. To directly compare the performance of human epididymal sperm in the zona-free hamster oocyte sperm penetration assay (SPA) with the results of human in vitro fertilization (IVF). DESIGN Sperm penetration assay was carried out with epididymal sperm retrieved microsurgically, and with ejaculated sperm obtained from fertile donors (internal controls). For direct comparison, SPA was performed with the same epididymal sperm sample used for IVF. PATIENTS, PARTICIPANTS Men with congenital absence of the vas deferens undergoing sperm aspiration as part of their infertility treatment and control donors who provided ejaculated sperm. RESULTS Epididymal sperm penetrated SPA with a score of 0% to 30%. The SPA scores for internal controls using ejaculated sperm was 30% to 71%. Linear regression analysis of the association between penetration scores in SPA and fertilization rate in IVF indicated a positive correlation that was highly significative. CONCLUSIONS These findings using SPA confirm previous reports on the fertilizing potential of human epididymal sperm and its ability to produce normal pregnancies. The good correlation between SPA and human IVF using epididymal sperm suggest that SPA is an excellent bioassay to test laboratory experimental conditions for improving fertilizing capacity of human epididymal sperm.

The importance of egg and sperm factors in predicting the likelihood of pregnancy from gamete intrafallopian transfer

The relative contribution of factors affecting the probability of pregnancy from gamete intrafallopian transfer was estimated using data from 218 cycles performed in San Antonio, Texas, and Orange, California. Mature eggs, all of which contained an expanded cumulus, were subclassified according to the corona radiata; those with a starburst corona were considered the most fully mature. Sixty-two clinical pregnancies were established, representing a pregnancy rate of 28.4%. Excluding 49 cases of male factor infertility, the pregnancy rate was 34.9%. Pregnancy rates were not significantly different according to age, cause of female factor infertility, parity, duration of infertility, stimulation protocol, or estradiol level. The only variables having a strong association with pregnancy were sperm and egg parameters. Sperm motility and morphology were statistically more important than sperm density. Based on odds ratios calculated from multiple logistic analysis, pregnancy was 3.80 times more likely if three or more fully mature eggs were transferred, 0.34 times as likely if motility were less than or equal to 30%, and 0.22 times as likely if normal morphology was less than or equal to 50%, controlling for other egg and sperm factors. If all egg and sperm factors in a given cycle were unfavorable, the probability of pregnancy estimated by the logistic model was 4%, whereas if all were favorable the probability of pregnancy in that cycle was 59%.