Constant decline in sperm concentration in infertile males in an urban population: experience over 18 years

To investigate semen quality in infertile men from an urban population over an 18-year period.

Retrospective study.

Andrology clinic at a city university hospital.

A total of 9,327 men were referred to the clinic for infertility investigation. After excluding those with azoospermia, 7,780 samples were evaluated.

Semen samples were analyzed within half an hour of production using computer-automated semen analysis and phase microscopy.

Sperm concentration, morphology, and motility; semen pH and leukocyte concentration; and patient age.

The median patient age over the study period was 31.6 years, with an increase from 30.8 years in 1986 to 34.4 years in 2003. The median sperm concentration was 10.25 million/mL for the entire period, with a decline from 27.75 million/mL in 1986 to 4.60 million/mL in 2003. The median proportion of normally shaped spermatozoa was 15%, and the proportion of motile spermatozoa was 21%. The pH increased from 7.4 in 1986 to 7.9 in 2003, and the median leukocyte concentration was 1.50 million/mL.

A constant decline in median sperm concentration was found in the infertile men. The reason for this remains unclear, although the high pH and leukocyte concentration indicates the involvement of infection.