Chromosomal analysis of unfertilized human oocytes

Summary. Unfertilized human oocytes were obtained from women in an in-vitro fertilization programme. The women had a mean age of 29\m=.\4years (range 24\p=n-\35years). Chromosomal complements could be analysed in 50 oocytes. Q-banding of the chromosomes facilitated identification of individual chromosomes: 34 oocytes (68%) had the normal haploid chromosomal complement, 14 complements were hypohaploid (28%), 1 complement was hyperhaploid (2%) and 2 had structural abnormalities (4%).(One oocyte had numerical and structural abnormalities.) The 16 abnormal oocytes were obtained from 15 different women. A conservative estimate of aneuploidy in this sample is 4%; however, the frequency of aneuploidy may be higher if there is a predis-position to chromosome loss during oogenesis. This study provides information on the largest series of karyotyped unfertilized human oocytes published to date