If your family has a hereditary genetic disease, you may want to look into ways to lessen the chance of transmitting the condition to your child. As a result, your fertility doctor may discuss PGD testing with you. Many medical procedures, on the other hand, might make patients feel unsure and frightened. The essential facts about Preimplantation genetic testing are described in detail below. With this knowledge, you and your spouse will be able to obtain a better understanding of IVF and PGD techniques, allowing you and your partner to feel more confident and empowered as you begin the process.
Preimplantation genetic testing is a laboratory method that allows couples to evaluate embryos prior to implantation in order to reduce, but not entirely eliminate, the risk of having a baby with certain genetic disorders. People with a genetically inherited ailment in their family can use preimplantation genetic diagnostic (PGD) to avoid passing it on to their descendants.
During preimplantation genetic testing of a frozen embryo, several steps take place. The embryos must be retrieved from cryopreservation and successfully thawed. At Reproductive Science Center (RSC), 98 percent of our embryos survive the thawing. However, embryos actually have to do better than just survive to be able to make it to the biopsy of PGT. The unfrozen embryos must have enough cells that they can withstand giving up some for the testing. So a patient may have four embryos thawed, but we are only able to biopsy three of them due to not having enough cells.
The cells that will be biopsied must come from the trophectoderm, or the cells destined to become the placenta, rather from those cells that will become the fetus. So the trophectoderm cells must be hearty and numerous.
Embryos are surrounded by an outer coating called the zona pellucida (shell) that holds together the individual cells of an embryo. One of the most common barriers to becoming pregnant with IVF is improper implantation of the embryo because it hasn’t “hatched” through the zona pellucida enabling it to implant in the uterus. A process called assisted hatching that involves a laser can be used with IVF to help embryos implant and increase the chances of pregnancy success.
In frozen embryo PGT, if the embryo has not already been hatched with the laser, the zona pellucida must be hatched. Then as the embryo re-expands, 5-6 cells are taken from the trophectoderm and sent for preimplantation genetic testing. Each embryo is numbered and the sample of cells is numbered to correspond to the embryo. The testing can be done on several different platforms (see above), but most all forms of PGT will tell us if there is a normal chromosome count and what
the sex is. If there is a specific gene mutation we are looking for, then we can also tell if the embryo is affected with the mutation.
Misdiagnosis is the greatest danger of all methods of Preimplantation genetic testing The main danger stems from a process known as "mosaicism," which has been observed in embryos. Mosaicism occurs when a single embryo contains numerous different types of cell lines. In other words, mosaicism occurs when a component of an embryo's cells is normal but another portion is defective. This could lead to inaccuracies in preimplantation testing results, such as failing to diagnose faulty embryos or incorrectly categorizing abnormal embryos as normal.
IVF does not always result in pregnancy, as many hopeful parents are aware. The chances of conception are driven by a range of factors, all of which are unique to your situation. If you want to know more about your chances of conceiving with IVF + PGD, talk to your doctor in detail and ask for pregnancy rates statistics. In the vast majority of situations, PGD testing is 100% accurate. As a result, doctors advise confirming Preimplantation genetic testing results during pregnancy.