Reassessment of sperm morphology of archival semen smears from the period 1980–1994

Abstract

SummarySeveral reports have suggested that sperm counts of normal men have declined in many geographical regions during the last decades. Deterioration of sperm morphology has also been reported in some studies covering long sample collecting periods. The original semen analysis data of our semen laboratory from the period 1980±1994 showed a signi®cant decline in the proportion of spermatozoa with normal morphology. The ®nding was, however, questioned because of changes in sperm morphology assessment criteria during the study period. In the present study 1745 smears were re-analysed to cover evenly the whole study period. The samples were examined in random order by using strict assessment criteria. Multiple linear regression analysis of the re-analysed data showed no effect of the year of sample delivery on sperm morphology between the years 1980 and 1994. However, there was a signi®cant decline in the proportion of normal spermatozoa with later year of men's birth.

Clinical significance of the low normal sperm morphology value as proposed in the fifth edition of the WHO Laboratory Manual for the Examination and Processing of Human Semen

“…This tendency toward a stricter approach over time was also illustrated in a publication by Horte et al [43], in which a series of sperm morphology smears from 1980 to 1994 were re-evaluated. The results showed that the observed decline in the percentage of morphologically normal spermatozoa observed over the 15-year period was mainly because of a stricter evaluation approach over the years.…”

Evaluation of the association of cigarette smoking with retention of excess cytoplasm by spermatozoa in infertile men

“…Sperm morphology is an independent predictor of in-vivo and in-vitro fertilization and is a sensitive indicator of exposure to different effects such as those of chemical compounds [36]. CD is a morphological feature necessary for normal sperm functions [17].…”

Sperm morphology: classification drift over time and clinical implications

“…When the previous technician reread the slides, it was found that the morphology values in fact did not change. Similarly, Horte et al (9) used reanalysis of slides to demonstrate a change in morphology from 1980 to 1994 that was explained by classification drift rather than population drift. In support of this hypothesis, particularly the effect of introduction of ''strict'' methodology, Menkveld (10) found that ''a stricter approach'' was responsible for the majority of the downward shift in morphology averages.…”

“…However, sperm morphology is also the most subjective component of a semen analysis, thus making it prone to interlaboratory and intralaboratory variation (6,7) and classification drift (8)(9)(10). Several morphology assessment systems exist, including the widely used Tygerberg strict (strict) criteria (11) and the World Health Organization (WHO) criteria (12,13).…”

“…Variation within labs for a single classification system is a documented phenomenon for WHO 2nd (8), WHO 3rd (9), and strict criteria (10). Furthermore, the propensity for becoming ''overly strict'' using strict criteria has been reported (6,14).…”