Clinical evaluation of the zona-free hamster egg penetration test in the management of the infertile couple. Prospective and retrospective studies

The search is on: finding accurate molecular markers of male fertility

Diagnosis of the fertility potential of a semen sample is essential for consistently high reproductive efficiency. The use of subfertile or infertile semen can have devastating consequences for those selling or using the semen. Therefore it is crucial to develop and use accurate diagnostic tests to determine the fertility of males and of individual semen samples. These diagnostic tests must be economically practical and provide consistent results. The goal of this review is to explore areas of fertility diagnostic research, including what we have termed functional and molecular tests, and consider the accuracy of each test. In this article, literature from several species is cited, and it is noteworthy that each diagnostic test may not be valuable in all species. Multiple functional and molecular tests will likely be needed to effectively characterize male fertility in each species.

The long-term predictive value of the zona-free hamster ova sperm penetration assay

Three hundred sixty-nine infertile couples were followed for 2 to 5 years in a study designed to determine the clinical long-term predictive value of the zona-free hamster ova sperm penetration assay (SPA). Semen analysis (SA), SPA, and a full infertility workup were done in all cases, and only couples in whom the female had no evident cause of infertility were included in the study. During the follow-up period, 106 couples (29%) achieved a pregnancy. Sixteen percent of 131 men who had an SPA of 0%, 23% of 120 men with 1% to 19%, and 48% of 118 men who had a penetration of greater than 19% impregnated their wives 2 to 5 years after the assays. Significant difference in fertility prognosis was found between those who had an SPA greater than 19% and those with an SPA less than 20% (48% versus 20%). Sperm penetration assay greater than 19% was predictive of higher pregnancy rates in both oligospermic (41% versus 17%) and unexplained infertile couples (52% versus 24%). The specificity and positive predictive values of the SPA were higher than those of the SA (77% versus 57% and 48% versus 37%). These findings emphasize the value and importance of the SPA in determining the long-term fertility potential of men.

The clinical value of conventional semen analysis

The objectives of this study were, firstly, to relate semen variables to treatment independent conception rates by life-table analysis after having accounted for known female factors; secondly, to assess the relationship between the length of involuntary infertility before investigation and the predictive value of semen parameters; and thirdly, to examine the relationship between the type of progressive spermatozoal motility and fertility outcome. Laboratory error in the assessment of semen variables was minimized by using one consistent observer. Seven hundred thirty-nine subjects were recruited to the study over a 34-month period, and a 96.5% follow-up rate was achieved. Where the female partner had regular spontaneous ovulation, no pelvic pathology, and more than 48 months' preceding infertility, the Grade 2 motile sperm density (the concentration of spermatozoa exhibiting slow or sluggish linear or nonlinear motility) was the variable that best predicted fertility outcome (X1(2) = 20.24, P less than 0.0001). Where the Grade 2 motile sperm density was below 5 X 10(6)/ml in the latter group (19%), no conceptions were reported at 32 months' follow-up. Semen variables were not of predictive value where there were fewer than 48 months' infertility before investigation, or where the female partner had ovulatory dysfunction or pelvic pathology.