Sperm morphology: assessment, pathophysiology, clinical relevance, and state of the art in 2017

Abstract

For over 30 years, sperm morphology assessment has been one of the most common tests in evaluation of fertility. This review examines the clinical relevance of sperm morphology assessment in the diagnosis of infertility and in assisted reproductive technology, as well as its analytical reliability. Publications on the pathophysiology, the analytical reliability of the test and its clinical relevance in diagnosis and in Assisted Reproductive Technology (ART) were evaluated. This review compared and discussed study methodologies and results, including patient characteristics, preparation, smear staining methods and classification systems. The assessment of the percentage of some abnormalities such as for example thin head, amorphous head, or bent or asymmetrical neck is of little clinical use, and their pathophysiology is not well explained as most are physiological traits. Some studies have highlighted correlations between the percentage of normal forms and functional sperm abnormalities, as well as correlations with ability to conceive in vivo and, in some situations, with the success of intra-uterine insemination (IUI) or conventional IVF. However, except in the case of some specific sperm defects (easy to detect with 99 or 100% of spermatozoa affected) and which are often linked to genetic disorders (globozoospermia, macrocephaly, decapitated sperm syndrome and fibrous sheath dysplasia), sperm morphology assessment has very poor sensitivity and specificity in the diagnosis of infertility. Moreover, there is very little evidence that indices of multiple sperm defects [sperm deformity index (SDI), teratozoospermia index (TZI), and multiple abnormalities index (MAI)] are relevant. Above all, many publications report a major lack of analytical reliability of this test, mainly in assessment of the details of sperm abnormalities. Many questions arise concerning how and when sperm morphology should be assessed, and how to interpret the thresholds of normal forms. Questions are raised on the real clinical impact of this test.

Cytoskeleton Structure in Mouse Sperm and Testes After 30 Days of Hindlimb Unloading and 12 Hours of Recovery

“…It is well known that under conditions of real space flight and various microgravity models, oxidative stress occurs due to the accumulation of reactive oxygen species and nitrogen oxide [51]. In turn, oxidative stress is one of the most well-studied factors leading to chromatin damage in spermatozoa [52,53], especially if the hormone concentrations are stable, there is a lack of toxic effects, and so on. Nevertheless, we did not observe a redistribution of morphological abnormalities after suspension, and the proportion of spermatozoa with an abnormal head did not differ in all study groups.…”

Optimization of laboratory procedures for intrauterine insemination: survey of methods in relation to clinical outcome

“…The questionnaire results confirm this hypothesis: Only half of the laboratories perform sperm morphology assessment of which only two use the Papanicolaou stain, as described by the WHO. A similar result was found in France (Gatimel et al ., ). The risk of not performing sperm morphology assessment is complex to speculate about, as on the one hand, one might miss specific severe abnormalities which lead to infertility (e.g., globozoospermia, 100% short motile tails, 100% severe ERC, and 100% stress‐induced elongated sperm heads) and, on the other hand, a poor performance may lead to unsuitability of the algorithm used for patient selection.…”

Computer‐aided sperm analysis, the new key player in routine sperm assessment

“…Morphology is a parameter subjected to strong inter‐laboratory variations, so much so that some consider it to be one of the most subjective parameters in sperm testing (Punjabi et al, ) and moreover some question its relevance (Gatimel, Moreau, Parinaud, & Léandri, ). Authors revealed that classification changes and standard modifications inside the successive editions of the WHO classification all played a part in keeping this parameter in blurred territory.…”