Selection of the most common chromosome abnormalities in oocytes prior to ICSI.

Abstract

So far, all preimplantation genetic diagnosis (PGD) protocols in use produce results after the eggs have been fertilized. However, these approaches are not acceptable for patients with moral objections to the generation and discard of supernumerary zygotes or embryos. In these circumstances, only those oocytes to be replaced may be inseminated. The purpose of this study was to develop a PGD protocol to diagnose first polar bodies (PBs) prior to Intracytoplasmatic Sperm Injection (ICSI) in order to inseminate only those oocytes found to be chromosomally normal. PB biopsy was performed 1 hour after ovum pick up, and after fixation, the PBs were analysed by FISH and the eggs inseminated by ICSI no later than 7 hours after retrieval. One third (33.3%) of the PBs were aneuploid. Fifty-four normal and 12 non-resolved oocytes were injected by ICSI, of which 65% became 2-PN zygotes. Embryo transfer on day 2 was possible in all 10 patients (average maternal age 35.2+/-3.2, range 29-39 years), of which 6 became pregnant with 8 fetuses (28.6% or 8/28 transferred embryos). The results indicate that PB analysis of some common chromosome abnormalities is feasible within time limits imposed by ICSI insemination (6 hours or less).