Preimplantation FISH Diagnosis of Aneuploidies

Preimplantation genetic diagnosis (PGD) has been introduced as a principally new approach to the prevention of genetic disorders, avoiding prenatal diagnosis and potential termination of pregnancy (1 ,2 ). It is based on the genetic testing of oocytes or embryos, with the purpose of establishing an unaffected pregnancy, rather than performing fetal diagnosis after at risk patients become pregnant, facing a risk for pregnancy termination if the fetus is affected. Although PGD was originally introduced for pre-existing genetic disorders (3 ,4 ), its application appears to be of special relevance for sporadic conditions, such as chromosomal abnormalities, which contribute significantly to pregnancy loss and infertility.