Abstract
Selection of a spermatozoon presenting both motility and normal morphology is one of the main concerns in intracytoplasmic sperm injection. Spermatozoa appearing as morphologically normal at the 400× magnification could carry various structural abnormalities that could negatively influence embryo development and pregnancy establishment, but only be detected with the use of higher optical magnifications. This led to the development of motile sperm organelle morphology examination (MSOME), which can achieve magnification ranging from 6300× to 13000×. Several approaches were used to classify spermatozoa. However, the prevalence of morphologically normal spermatozoa in MSOME is low (usually less than 5%). The most striking abnormalities are vacuoles, thought to be of acrosomal and/or nuclear origin and related to failure of sperm chromatin condensation. Twelve years after the introduction of MSOME, many questions remain unsolved. A consensual definition of a ‘normal’ spermatozoon and a classification of abnormal spermatozoa accepted by all workers in this field is still awaited. We are far away from understanding the nature and the consequences of the vacuoles.
Financial & competing interests disclosure
The authors have no relevant affiliations or financial involvement with any organization or entity with a financial interest in or financial conflict with the subject matter or materials discussed in the manuscript. This includes employment, consultancies, honoraria, stock ownership or options, expert testimony, grants or patents received or pending, or royalties.
No writing assistance was utilized in the production of this manuscript.