The Clinical Interpretation of 1000 Semen Analyses Among Applicants for Sterility Studies

Abstract

In 1000 consecutive semen analyses among applicants for sterility study, 7.1% were sterile because of azoospermia. Of the remainder, 129 were classified as fertile since the wives conceived within a few months after the examination. These were analysed separately from the 800 specimens of unknown fertility and distribution curves prepared for 3 factors: sperm density, percentage of motility two hours after collection, and the percentage of normal, oval sperm heads. Median values for the fertile men were 82 million per cc, 54% motile and 88% normal sperm heads. It was assumed that a specimen of high quality throughout represented a probability for fertility of about 90%, and that the probabilities for those men whose semen showed values below the median were roughly proportional to the percentage oi fertile men falling into the same group. The fact that low density is correlated with poor motility and poor morphology was confirmed. The assumption was made that the product of probabilities for each of the 3 factors was the most valid index of the fertility of any single specimen, and, based upon this, a nomogram was constructed for easily determining this index. The use of this "fertility index" has been of clinical value in the comparison of selected groups of men, and for the interpretation of changing quality in the same individual.