In medicine and (clinical) genetics preimplantation genetic diagnosis (PGD) (or also known as Embryo Screening) refers to procedures that are performed on embryos prior to implantation, sometimes even on oocytes prior to fertilization. PGD is considered an alternative to prenatal diagnosis. Its main advantage is that it avoids selective pregnancy termination as the method increases the chances that the baby will be free of the disease under consideration. PGD thus is an adjunct to assisted reproductive technology, and requires in vitro fertilization (IVF) to obtain oocytes or embryos for evaluation.

PreImplantation Genetic Diagnosis (PGD)

The quality of the eggs is of primary importance to create healthy embryos. In general, it is a woman's age that determines the quality of her eggs.

For the first time, women of mature age (over 38) are able to have their embryos checked using PGD to select the healthiest and most robust embryo. PGD is done before the embryo’s genetic material becomes ‘active’, when the cells inside the embryo are still all identical and each cell is still capable of becoming any part of a baby. This method does not damage the developing embryo.

This process involves the removal of two cells when the embryo is at the 8 cell stage allows the checking of chromosomes for abnormalities. PGD for gender selection can also be done at this time if the couple want to balance their family. PGD will be completed on day 3 of embryo development.