الفهرس 
IntroductionOnly 14 pages are availabe for public view
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Abstract
Preimplantation genetic diagnosis is a relatively new procedure in which eggs or embryos are tested for certain genetic conditions prior to being replaced in the uterus. The PGD falls into two categories. High risk PGD which is carried out for patients at high risk of transmitting a genetic or chromosomal abnormality to their children. Low risk PGD (preimplantation genetic screening) which is carried out for infertile patients undergoing IVF with the aim of increasing the IVF pregnancy rates as in cases of advanced maternal age, couples with repeated IVF failure and couples with repeated miscarriages. There are two main approaches in PGD. The first and less informative is to remove a polar body with a micropipette. The second and preferred method is to remove one or two cells ?blastomere? with a micropipette from the embryo on day 3. The PGD depends mainly upon two analytical procedures. One is polymerase chain reaction (PCR) which can be used for the diagnosis of single gene defects at the DNA level. The second is fluorescence in situ hybridization (FISH) which is used for chromosomal abnormalities diagnosis as well as sexing of embryos. The PGD eliminates the need for selective abortion which is ethically, legally and religiously unaccepted.