Minimal criteria of sperm quality for insemination and IVF therapy

Minimal criteria are poorly established because prognosis of success for an individual couple is possible only statistically. In the past, therefore, there was wide variation in the minimal semen criteria required to ensure that therapy for male subfertility had a chance of being successful. The aim of this study was to define minimal criteria for semen parameters in husbands of women undergoing IVF and insemination at the Department of Obstetrics and Gynaecology, University of Göttingen. The results prove that the establishment of minimal semen criteria is only possible to a limited extent. At least 10 x 10(6) spermatozoa/ml, of which at least 30% are motile and 15% have progressive motility, are required for IVF or insemination therapy, despite the fact that pregnancies can be achieved with lower parameters. As a minimum, 20% of spermatozoa should be of normal morphology. On average, a curvilinear velocity of 35 microns/sec and a straight-line velocity of 15 microns/sec are needed. It is questionable, however, if in future these minimal criteria will still be relevant. The successful injection of one spermatozoon into an oocyte (intracytoplasmic sperm injection, ICSI) suggests that all the semen quality parameters which have been demanded in the past are no longer of any value. Fertilization and pregnancy can be achieved by ICSI even with immotile spermatozoa, spermatozoa which have not undergone the acrosome reaction, spermatozoa without tails, and morphologically aberrant and/or immature spermatozoa.