The effect of intracytoplasmic sperm injection and semen parameters on blastocyst development in vitro

The present study compares the development and quality of blastocysts deriv ed from conventional oocyte insemination with those derived from intracytop lasmic sperm injection (ICSI). Oocytes were collected from patients undergo ing ovarian stimulation,vith human menopausal gonadotrophins for IVF, Patie nts with normal semen were assigned to conventional oocyte insemination whi le those with progressive motility < 20% and/or normal sperm morphology les s than or equal to4% mere assigned to ICSI. Resulting embryos were cultured for up to 6 days. The mean number and percentage of embryos reaching the b lastocyst stage and the mean number and percentage of blastocysts of high q uality on days 5-4 were assessed for both treatment groups and compared. Th e influence of paternal factors (sperm concentration, motility, progressive motility; morphology) on blastocyst development and quality were assessed by regression analyses. Significantly more ICSI-derived embryos arrested at the 5- to 8-cell stage (P = 0.024) concomitant with the activation of the paternal genome than those derived from conventional oocyte insemination, S ignificantly fewer ICSI-derived embryos reached the blastocyst stage on day s 5-6 (P < 0.001) and significantly fewer ICSI-derived embryos were of high quality (P = 0.002) compared with conventional oocyte insemination. When t reatment groups were combined and evaluated by regression analysis, progres sive motility and sperm morphology were significantly correlated with dimin ished blastocyst development and quality (P < 0.05). From these data, we co nclude that paternal factors and/or performing ICSI in cases of severe male factor infertility may have a detrimental effect on blastocyst development and their quality.