A quantitative study of sperm head ultrastructure in subfertile males with excess sperm precursors

To make an objective comparison between sperm head ultrastructure in fertile subjects and a subfertile cohort with an excess of immature germinal elements in the ejaculate. A quantitative analysis of ultrastructural features of the sperm head using transmission electron microscopy in the defined groups. Ten men of proven fertility as controls and 10 subfertile subjects with a persistent excess of sperm precursors in the ejaculate were investigated. The Infertility Clinic at Queen Charlotte’s and Chelsea Hospital, London. Each individual in the study achieved a score for a range of previously defined features of sperm head ultrastructure. These scores provided the basis for comparison between fertile and subfertile subjects. Subfertile individuals were found to have motile sperm with significantly more hypoplastic, detached, and abnormally shaped acrosomes than fertile controls. Sperm nuclei in these subjects also contained significantly more intranuclear vacuoles and immature chromatin and were associated more commonly with cytoplasmic droplets than fertile controls. Men with an excess of sperm precursors in the ejaculate have motile sperm with a range of abnormalities involving the nucleus and acrosome to account for reduced functional competence.