OOCYTE IN-VITRO MATURATION AND ICSI

Intracytoplasmic sperm injection (ICSI), treatment of severe male infe rtility allows an accurate evaluation of oocyte maturity at recovery a fter corona - cell removal. In cycles comprising a GnRH analog desensi tization and a stimulation by hMG or FSH, 12% of oocytes aspirated fro m follicles (> 14 mm), 34 hours post - hCG are still immature, in prop hase or metaphase 1, They are able to achieve meiosis in vitro in 66% of the cases and will be fertilized (2 PN) by ICSI in 51% of the cases as the in vivo mature oocytes of the same cohort, Nevertheless, the q uality of cytoplasmic maturation and consequently of embryonic viabili ty remains to be assessed as there still are few pregnancies arising f rom in vitro matured oocytes, ICSI also represents the only way to obt ain normal fertilization in some exceptional but observed anomalies of oocyte maturation, particularly when there is a lack of zona reaction leading to repetitive polyspermy in conventional IVF.