For some patients, the need to transfer genetically normal embryos is paramount. To help achieve this, preimplantation genetic screening (PGS), also known as preimplantation genetic diagnosis (PGD), is an option to test embryos prior to transfer.
Who needs PGS/PGD?
PGS/PGD is not necessary or even recommended for all couples. However, in some cases, it is an important tool to assess the genetic makeup of the embryos. Couples in which one or both are carriers of diseases such as cystic fibrosis, Huntington’s disease, sickle cell disease, muscular dystrophy, polycystic kidney, Tay-Sachs, and hemophilia may opt to test embryos prior to transfer to determine if they are positive for the disease. Couples with a single gene defect, a situation in which one partner either has the disease or is a carrier for the disease, can utilize PGS/PGD through a genetic probe to determine if the trait has been passed on. PGS/PGD can also be used for couples with recurrent miscarriage, recurrent IVF failure, women over 40, and genetically normal couples with balanced translocation.
How is it done?
The eggs are first obtained via retrieval and are exposed to sperm. On day 3 after the retrieval, the resultant embryos are observed under the microscope to determine which have fertilized and how many can be biopsied. A single cell from the embryo is removed and sent to the reference lab for genetic testing. By day 5 after transfer, the results are received from the lab and a decision can be made about how many embryos are approved for transfer.
As with most fertility treatments, PGD/PGS is not a perfect science. But it can help identify and decrease the risk of passing along genetic defects to offspring. To read more about this technique and watch a fantastic short video of an embryologist from Austin IVF performing PGD, please visit http://www.txfertility.com/07PGD.php.
For more information please visit our website at www.txfertility.com or call us at (512) 451-0149.