Clinical value of sperm morphology for in-vivo fertility: comparison between World Health Organization criteria of 1987 and 1992

The World Health Organization (WHO, 1992) has suggested new criteria for scoring sperm morphology. This study compares the clinical value of the new criteria, i.e. classification of a man as fertile or infertile, to those previously established by the WHO (1987). Papanicolaou-stained semen smears from 166 men attending our infertility clinic, whose fertility status was known, were scored using both methods. Using logistic discriminant analysis for compositional data, no difference between these two sets of criteria with respect to predicting pregnancy outcome was observed. The categorization of the abnormalities (head, midpiece, tail) provides no extra clarification. The WHO (1992) cut-off point of 30% for normal forms is not appropriate, as approximately half of the men in the fertile group had a normal sperm morphology below this limit. In conclusion, the present WHO (1992) classification of sperm morphology is of no additional clinical value. Studies on sperm morphology should concentrate on obtaining biological data on, and measurements of, spermatozoa which are functionally active. Only then can the definition of normal be achieved and clinically useful criteria be adopted.