[In-vitro-fertilization: chromosome analysis of unfertilized human oocytes]

Chromosomal abnormalities and abnormal embryonic development have been observed after human in vitro fertilisation (IVF). Such investigations are not permitted according to the ethical guidelines approved by the IVF team in Berlin ("Berliner Modell"). However, the chromosomal status was studied in oocytes which remained unfertilised in a human IVF programme. In 50 fertilisation attempts the chromosomes of 62 oocytes could be analysed. 45 of the oocytes were in the process of meiotic maturation. One of these showed abnormalities in the first meiotic division and seven during the second meiotic division. After fertilisation in addition to normal embryos, all of which were transferred to the mother, three embryos were triploid and six oocytes were fragmented. The results prove that in human IVF chromosome abnormalities can occur in oocytes already before fertilisation. The importance of the results for later stages of embryonic development is discussed.