Confirmation of diagnosis in preimplantation genetic diagnosis (PGD) through blastocyst culture: Preliminary experience

Three cases of preimplantation genetic diagnosis (PGD) (two for sexing and one for aneuploidy screening) are presented. Embryo biopsy was performed at day 3 and diagnosis was established with fluorescent in situ hybridization (FISH). Embryos not used for replacement were cultured in sequential media for blastocyst development. Blastocyst rate was 39.3 per cent. Confirmatio ns of diagnosis were established with FISH in blastocysts and arrested embr yos. Mosaicism was observed in 7/8 blastocysts (mean number of cells analys ed: 55.5) and 5/8 arrested embryos. The percentage of abnormal cells was 17 .1 per cent for blastocysts and 54 per cent for arrested embryos. Polyploid cells were observed in 4/8 blastocysts. Confirmation of diagnosis at the b lastocyst stage is a useful tool in PGD. Copyright (C) 1999 John Wiley & So ns, Ltd.