Preimplantation Genetic Testing (PGT) is a procedure used to identify genetic differences in embryos created with in vitro fertilization (IVF) . PGT is performed before embryos are transferred to the uterus, and the goal is to significantly reduce the chances of transferring an embryo with a specific genetic condition or certain types of chromosome abnormalities. PGT can be performed for any IVF cycle, but the decision to have this testing is complex and should be made after careful discussion with your physician or genetic counselor. There are three types of PGT:
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PGT-A: This is an analysis of embryo cells to determine if there is the normal amount of chromosomes. An unequal division of either sperm or egg cells can result in an embryo having too few or too many chromosomes. PGT-A can ensure that the embryo selected for transfer has the correct number of chromosomes, thereby reducing the chances for a failed IVF cycle and reducing the chance of miscarriage.
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PGT-M: This type of PGT is used to reduce the chance of a specific genetic condition occurring in children. Patients who have a genetic condition such as neurofibromatosis type 1 or Marfan syndrome that could be passed on to their children may seek IVF with PGT-M.
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PGT-SR: This type of PGT is used to identify structural rearrangements in chromosomes that can cause genetic disorders.
If PGT is part of your plan, you will need to undergo an IVF cycle to retrieve eggs and create embryos. The embryos are monitored in the laboratory until day 5 or 6 after fertilization when they are referred to as blastocysts. At that point, a small number of cells are removed from each embryo and shipped to an outside laboratory for PGT.
