[Cytogenetic analysis of human oocytes and the process of their maturation outside the body].

A cytogenetic analysis of human oocytes, after their removal from follicles and during extracorporeal maturation, has been performed. The heterogeneity of follicular oocytes according to the character of nuclear chromatin was established. It is probably related to the rate of reinitiation of meiosis in vivo and to the rate of atretic process. The dynamics of human ovum maturation in vitro was studied. 50.8% oocytes reached metaphase II in 46 hours of cultivation, but only 22.8% of these had no chromosomal aberrations. It is supposed that the high rate of chromosomal anomalies in vitro is a possible consequence of degenerative changes of oocytes that started still in vivo.