Factors associated with premature chromosome condensation (PCC) following in vitro fertilization.

From January 1989 to July 1990 a total of 562 oocytes was fixed in our In Vitro Fertilization Program, while cytogenetic data were collected in the case of 433. Forty-eight of these (11%) had a set of oocyte chromosomes in metaphase II, and at least one other set of sperm chromosomes prematurely condensed in the form of single chromatids. In the literature this phenomenon, frequent in our experience, has not been separately studied by many authors. Comparative studies with diverse parameters have shown a significant correlation between the same phenomenon and the use of follicle-stimulating hormone supplementation in ovarian stimulation protocols. Also, in some cases we found a high percentage of repetition of the phenomenon in one patient.