Utrastructural analysis of asthenozoospermic ejaculates in the era of assisted procreation

OBJECTIVE: To define by transmission electron microscopy (TEM) analysis, the prevalence of sperm tail defects of genetic origin among men suffering for a reduced or absent sperm motility. DESIGN: A retrospective study. SETTING: Andrology Clinic, University of L'Aquila, Italy. PATIENT(S): The 120 ejaculates of infertile men with a forward motility (FM) < or =20% were compared to 200 ejaculates with a FM >20%. All ejaculates had a sperm vitality >50%. INTERVENTION(S): Some 25-50 tails were analyzed by TEM in each ejaculate. MAIN OUTCOME MEASURE(S): Receiver operating characteristics (ROC) analysis was applied by plotting the FM of cases with or without genetic tail defects detected by TEM. RESULT(S): The area under the ROC curve was 0.96 (95% confidence interval 0.92-0.98). The positive predictive accuracy for genetic tail defects in ejaculates with 0% FM was 46%. Three of 17 cases with genetic tail defects were classified as false negative when TEM analysis was restricted to ejaculates with 0% FM. A FM < or =7%, allowed the identification of all cases with genetic tail defects. CONCLUSION(S): The TEM analysis identifies sperm tail defects of genetic origin and should be restricted to ejaculates with severe asthenozoospermia (< or =7% motile sperm) and sperm vitality >50%.