4. Developmental ability of chromosomally abnormal human embryos to develop to the blastocyst stage.
A correlation between morphology, developmental competence and chromosome abnormalities is established. However, embryo selection remains one of the most arduous tasks in assisted reproduction. The authors have undertaken this study in order to determine which chromosomal abnormalities are compatible with development to the blastocyst stage. Embryos diagnosed by preimplantation genetic diagnosis (PGD) as chromosomally abnormal or unsuitable for transfer were cultured to day 5 or 6. Morphology and development were observed daily. After extended culture, embryos were fixed and analysed by two rounds of FISH with the same probes used for PGD. Even though there is a strong selection against chromosomally abnormal embryos, extended culture to day 5 or 6 cannot be used as a reliable tool to select against clinically relevant chromosome abnormalities such as trisomies.
Sandalinas M, Sadowy S, Alikani M, Calderon G, Cohen J, Munne S. (2001) Developmental ability of chromosomally abnormal human embryos to develop to the blastocyst stage. Hum Reprod. Sep;16(9):1954-1958.