Objective: To investigate the frequency of headless, or unnucleated, spermatozoa, determine its percentage and evaluate its possible correlation with other semen parameters.
Study design: Semen specimens from 94 subfertile men, aged 24-53 years (mean +/- SD 33.3 +/- 6.3) and from 52 fertile men, aged 24-44 (33.3 +/- 4.1) were studied. Two semen specimens were examined from each individual, with a six- to eight-week interval. Sperm morphology was evaluated from Papanicolaou-stained smears, and the classification of abnormal sperm forms was made according to the guidelines of the World Health Organization.
Results: The percentage of headless spermatozoa was 9.0% +/- 8.8 in subfertile and 2.7% +/- 3.1 in fertile men. Headless spermatozoa existed in semen specimens from 90% of subfertile and 70% of fertile men. Of subfertile men, 23.4% had headless spermatozoa at a higher percentage than the highest normal limit found in sperm smears from fertile men.
Conclusion: In some cases of subfertile men with a high percentage of headless spermatozoa, their infertility can be attributed to the cause of this morphological abnormality. Moreover, tails but not heads were found in semen specimens from subfertile and fertile men.