Background: Severe sperm motility impairment results in human infertility, which can be overcome by ICSI. Whether some particular, possibly genetic, flagellar abnormalities can influence embryonic development is a matter of debate.
Methods: Analysis of ultrastructural flagellar abnormalities and ICSI outcomes with ejaculated spermatozoa in a series of 21 infertile patients with asthenozoospermic or dyskinetic spermatozoa due to a primary and specific flagellar abnormality was carried out.
Results: Patients were sorted into six categories according to flagellar ultrastructural defects. Oocyte fertilization occurred in the 21 couples with a mean 2PN fertilization rate reaching 61.85%. No difference was observed in the kinetics of in vitro development or in the morphological quality of the embryos between the different types of flagellar abnormalities. Pregnancy occurred in 12 couples (57.1%) and delivery in nine couples (42.86%). Both the implantation rate and the clinical pregnancy rate per cycle were lower in type III abnormalities and in patients with an initial sperm motility less than 5%.
Conclusions: The rate of ICSI success may be influenced by the type of flagellar abnormality. ICSI provides a suitable solution for patients with sperm flagellar defects but raises the question of the consequences of a specific (and primary flagellar) abnormality on oocyte fertilization, on embryo and fetal development as well as on live birth.