In assisted reproductive technology (ART), the aim of sperm cells’ preparation is to select competent spermatozoa with the highest fertilization potential and in this context, the intracytoplasmic sperm injection (ICSI) represents the most applied technique for fertilization. This makes the process of identifying the perfect spermatozoa extremely important. A number of methods have now been developed to mimic some of the natural selection processes that exist in the female reproductive tract. Although many studies have been conducted to identify the election technique, many doubts and disagreements still remain. In this review, we will discuss all the sperm cell selection techniques currently available for ICSI, starting from the most basic methodologies and continuing with those techniques suitable for sperm cells with reduced motility. Furthermore, different techniques that exploit some sperm membrane characteristics and the most advanced strategy for sperm selection based on microfluidics, will be examined. Finally, a new sperm selection method based on a micro swim-up directly on the ICSI dish will be analyzed. Eventually, advantages and disadvantages of each technique will be debated, trying to draw reasonable conclusions on their efficacy in order to establish the gold standard method.
The aim of this study was to determine the value of basal FSH as a predictor of assisted reproduction outcome in women >or=35 years undergoing ovarian stimulation with gonadotrophin-releasing hormone (GnRH) antagonist. A retrospective clinical study was carried out on 83 infertile women, 35-45 years old, divided into three groups according to their day 3 FSH concentration (group A = FSH 10 and <15 mIU/ml, group C = FSH >15 mIU/ml). Patients underwent ovarian stimulation with a GnRH-antagonist protocol. Group A women had significantly higher basal inhibin B concentrations (P < 0.001), lower cancellation rate (P < 0.001), required a significantly lower dosage of recombinant FSH (P < 0.0001) and had significantly higher oestradiol concentration under stimulation compared with the other groups (P < 0.0001). Oocyte and embryo numbers were comparable in all groups, although groups B and C had more low quality embryos compared with group A. The number of metaphase II oocytes and embryos was related to patients' ovarian reserve markers only in group C. Pregnancy and delivery rates were 35 and 22.5% in group A, 22.2 and 16.6% in group B and 5 and 0% in group C. It is concluded that a basal FSH cut-off of 10 mIU/ml seems predictive of ovarian reserve, while basal FSH cut-off of 15 mIU/ml seems predictive of pregnancy potential and probably of oocyte quality.
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