Preimplantation Genetic Diagnosis is a recent medical development that is always combined with application of IVF. Couples with indication to PGD are those with a partner suffering from a genetic disease or with both partners bearing a genetic disease trait, and thus having strong possibility of transferring the disease to their child. In the past, such couples having achieved pregnancy were tested with amniocentesis at the 2nd trimester of pregnancy; if the embryo was found to be suffering from the genetic disease then the couple would proceed to termination of the (already advanced) pregnancy which is a traumatic and quite dangerous experience. Today, these couples have the opportunity to follow a typical IVF program that includes the delicate removal of 1-2 cells from each of the occurring embryos usually at the 3rd day of their growth. The examination of these cells using advanced techniques may help to detect whether the specific embryo from which the correspondent cells were obtained suffers from the disease or not. Thus in a short period of time (1 or 2 days) we are able to know which of the embryos are healthy and proceed to transfer of these embryos only. The most common indication for PGD in Greece is the case of couples with both parents bearing b-thalassemia trait who have a 25% chance to give birth to a child suffering from the disease.
Finally, during the recent years a long international debate exists on whether PGD should be also suggested to couples with history of numerous IVF failures or numerous unexplained miscarriages arguing that the cause may be located to the creation (by those couples) of embryos bearing chromosome disorders that are unable to be implanted or that are aborted. This knowledge is of great value for those couples as they can receive now reliable genetic advice on their reproductive future.