Sperm parameters in men with suspected infertility. Sperm characteristics, strict criteria sperm morphology analysis...

To determine the distribution of sperm abnormalities in a population of suspected infertile men presenting for the initial investigation of male factor infertility.

Results obtained in the analysis of sperm viability, motility, conventional morphology (including 12 sperm anomalies), strict criteria sperm morphology analysis (SCSMA) and hypoosmotic swelling test (HOST) were compared in oligozoospermic (< 5.0, 5.1-10.0 and 10.1-20.0 x 10(6)/mL), normozoospermic (20.1-40.0, 40.1-100.0 and 100.1-250.0 x 10(6)/mL) and polyzoospermic (> 250.0 x 10(6)/mL) semen samples from 233 suspected infertile men.

Percentage of sperm viability, category a and categories a plus b of sperm motility, oval-headed sperm, and normal-headed sperm according to SCSMA and HOST had a direct relationship with sperm counts (P < .001). Percentage of amorphous heads, pinheads, tapering and combined defects showed an inverse relationship with sperm counts (P < .001), whereas the percentage of large-headed sperm was highest in semen with > 40.0 x 10(6)/mL (P = .003) and of neck/midpiece defects was lowest in semen with < 10.0 x 10(6)/mL (P = .03). No significant differences were found in the percentage of small heads, double heads, round heads, partially elongated heads, cytoplasmic droplet and tail defects. Based on the cutoff points established previously for the sperm characteristics analyzed, normal values were found in semen with > 250.0 x 10(6)/mL (viability and motility), > 100.0 x 10(6)/mL (conventional morphology) and > 40.0 x 10(6)/mL (SCSMA and HOST).

The incidence of defective spermatozoa is lowest in semen with the highest sperm count. However, sperm abnormalities that affect male fertility may be detected at any level of sperm density. The data indicate that an increase in any sperm abnormality should be regarded as a possible cause of decreased fertility.