Sperm morphology assessment: historical review in relation to fertility

Abstract

Careful analysis of sperm morphology has always been an important part of a routine semen examination. However, the usefulness of sperm morphology assessment as a predictor of a man's fertilizing potential has often been challenged due to different classification systems, various slide preparation techniques and inconsistency of analyses within and between laboratories. Automated sperm morphology analysis instruments may overcome the subjective nature of visual assessments of sperm morphology, but the technical problems are numerous and the validity of these instruments has still to be proven. Having reviewed the literature, it seems clear that there is general agreement concerning the clinical relevance and predictive value of this single semen parameter in vivo and in vitro. Nevertheless, even in cases of severe teratozoospermia, fertilization may be possible. Studies on the acrosome reaction are very promising for patients with severe sperm morphology abnormalities that do not have major effects on the fertilizing potential. Most promising is the development of intracytoplasmic sperm injection (ICSI) as the treatment of first choice in cases of severe teratozoospermia with failed fertilization in vitro. Normal fertilization and pregnancy rates can be obtained with ICSI in the presence of extreme teratozoospermia, suggesting that sperm morphology may be important in spermatozoa-zona binding, penetration and spermatozoon-oocyte fusion but fails to be of any predictive value once the spermatozoon reaches the cytoplasm of the oocyte. To conclude, accurate and strict sperm morphology assessment is very useful in evaluating a patient's fertilizing potential, with the main advantage that the methods used to examine this parameter are easy to learn on equipment found in most laboratories.

Sperm morphology assessment: diagnostic potential and comparitive analysis of strict or WHO criteria in a fertile and a subfertile population

“…The clinical value of sperm morphology as a predictor for fertility remains controversial, due to many different factors such as different classi®cation systems, various slide preparation techniques and inconsistency of analyses within and between laboratories (Baker & Clarke, 1987;Ombelet et al, 1995a). Despite these methodological pitfalls, sperm morphology seems to be an excellent predictive parameter in in vitro fertilization programmes and the studies supporting this statement are numerous (Kruger et al, 1986Liu & Baker, 1988;Oehninger et al, 1988;Chan et al, 1989;Hinting et al, 1990;Enginsu et al, 1991;Kobayashi et al, 1991;Grow et al, 1994;Ombelet et al, 1994).…”

Sperm function and assisted reproduction technology

“…Therefore, our data confirmed the paramount contribution of normal sperm morphology to successful fertilization and the importance of an accurate evaluation of the percentage of morphologically normal spermatozoa, as well as its value for andrological diagnosis. 14,19,[190][191][192] Obviously, this good predictive power of normal sperm morphology is based on the fact that sperm morphology appears to be closely correlated with other sperm functions, as it could be shown for sperm zona binding ability, 22,193 acrosomal functionality, 26,27,194 motility 21,58 or the sperm cell's own ROS production. 34 However, it is a good reason to believe that sperm morphology is a stable or even the most stable parameter, as the morphological phenotype of spermatozoa is genetically determined and stays relatively constant with respect to the type of abnormalities and the percentage of normal forms.…”

Does Training Assist Medical Laboratory Scientists with Better Evaluation of Sperm Morphology?

“…In the absence of sophisticated first world technologies such as sperm functional assays (sperm zona binding, acrosome reactions), the evaluation of bioche-mical markers (Reactive oxygen species, creatinin kinase) and genetic investigations (chromatin packaging, DNA breakages), sperm morphology can be used as clinical tool to assist in the therapeutic choice 6,7,8,9,10 However, the value of sperm morphology as predictor of a man's fertilizing potential has often been challenged due to different classification systems 11 . Several factors are responsible for this technical variation including differences in the methods used to prepare and stain specimens 12,13 differences in proficiency among technicians 14,15,16 and inherent differences in classification criteria and methods 17,18,1,19. The discrepancies in laboratory results have increased to such an extent that some investigators often refer to the semen analysis as the 'neglected test.…”