High rate of isolated teratospermia in a population of fertile men and the questionable clinical utility of sperm morphology.

Objective: To better understand the impact of sperm morphology on fertility by assessing sperm morphology in a population of known fertile men. Design: A prospective cohort study. Setting: Fertility center associated with the university. Patients: Healthy men >18 years of age were recruited to provide one semen sample before a vasectomy appointment scheduled between March 2020 and November 2022. Patients were included in the study when they had at least one biologic child and no history of difficulty achieving pregnancy or fertility procedures. Interventions: None. Main Outcome Measures: Sperm morphology. Results: A total of 68 patients (mean age 36.7 years) were included. Thirty-eight (55.9%) patients had 3% or lower normal sperm morphology, including two patients who had 0 normal morphology. The most common morphologic abnormalities were head-shaped defects (n = 59, 84.3%), followed by coiled tails (n = 14, 20.3%). Count, concentration, motility, and progressive motility were normal in >90% of patients. Conclusions: More than half (55.9%) of fertile male patients had lower than normal sperm morphology in our study. The results of our study further question the clinical relevance of sperm morphology on fertility outcomes and when the current approach in assessing morphology is too strict.