RESUMEN
OBJECTIVE: To characterize methodological changes in sperm morphology assessment and to correlate sperm morphology with clinical outcome. DESIGN: In this observational study, sperm morphology profiles of patients were analyzed. The percentages of morphologically normal spermatozoa were evaluated with respect to changes in morphology assessment criteria; male aging; and prognostic value for outcomes after in vitro fertilization (IVF)/intracytoplasmic sperm injection (ICSI). SETTING: Diagnostic and clinical laboratories. PATIENT(S): A total of 8,846 men who visited the diagnostic laboratory; 133 samples from a sperm bank; and 3,676 IVF/ICSI couples. INTERVENTION(S): None. MAIN OUTCOME MEASURE(S): The percentage of morphologically normal spermatozoa in semen samples. The regression of the individual morphologically normal cell profiles. The relation between the percentage of normal forms with pregnancy outcome after IVF/ICSI. RESULT(S): The percentage of morphologically normal spermatozoa showed a decrease from roughly 30%-80% in 1984 to 0%-10% since 2004. With added evidence from sperm bank samples, this decrease was found to be attributable mainly to changes in morphology assessment criteria. Furthermore, an intraindividual aging effect of 0.51% per year was observed. A statistically significant relationship was found between decreases in percentage of normal forms and a lower probability of ongoing pregnancies after IVF, although the area under the curve was only 54%. CONCLUSION(S): Methodological changes had a strong effect on the percentage of morphologically normal spermatozoa over the past few decades. In addition, male aging results in decreasing sperm morphology. The percentage of morphologically normal spermatozoa has no prognostic value for individual IVF/ICSI patients.
