CGH EMBRYO SELECTION IN WOMEN POLYCYSTIC OVARIAN SYNDROME (PCOS)
For a human embryo to be “competent” it must have all 46 chromosomes intact. Microscopic (morphologic) embryo grading methods while improving the ability to identify good quality embryos, are incapable of recognizing its chromosomes and as such are incapable of reliably identifying and selecting “competent” embryos for transfer. The recent introduction of a genetic test known as Comparative Genomic hybridization (CGH, by achieving this objective, is the closest to being a “silver bullet” when it comes to assessing embryo “competency.
At best, 50% of a young woman’s eggs are chromosomally normal and thus capable, upon fertilization , of generating embryos that are “competent” ( most likely to propagate normal babies ). As a woman ages (beyond her early thirties), progressively fewer of her eggs will be chromosomally normal (“competent”) and by 45 years of age, the percentage of competent eggs drops to under 10%. “Competent” eggs, upon being fertilized with healthy sperm will in >80% of cases propagate “competent” embryos
Women with Polycystic Ovary Syndrome (PCOS) tend to be very high responders to fertility drugs, often producing a large number of follicles and eggs. Unfortunately when this happens, a much higher than normal percentage of their eggs tend to have an irregular number of chromosomes (aneuploid) and are thus are incapable of propagating euploid (“competent”) embryos”.
CGH-based embryo selection provides a rational approach to selecting “competent” for transfer to the uterus in women with PCOS.