What is involved in PGD?
Preimplantation genetic diagnosis uses routine IVF and a special form of fertilisation of the woman’s egg by a man’s sperm. Hormones are used to stimulate her ovaries and enable the collection of a number of eggs, or oocytes. After the eggs are removed, they are fertilised in the laboratory with sperm using a technique called ICSI. With ICSI the embryologist will inject a single sperm into the main part of an egg, allowing the two to join, which is fertilisation. ICSI maximises the chances of sperm fertilising the egg and ensures that the genetic test on the fertilised embryos is clean and not contaminated by extraneous bound sperm, i.e. ones that become attached but have not penetrated the egg. Any eggs that are successfully fertilised are allowed to divide and multiply until they are 3 days old (post egg collection), when they contain about 8 cells. At this time one or two cells are removed in order to test for the specific genetic condition in question. The cells are then tested to
