Preimplantation Genetic Diagnosis / Preimplantation Genetic Screening
Preimplantation testing of embryo(s) can be performed to test for known genetic disorders that a person or couple may carry. This process is called preimplantation genetic diagnosis, or PGD. Testing can also be done to screen the embryo(s) to determine if it carries a genetic imbalance such as trisomy 21, which indicates Down syndrome. This process is called preimplantation genetic screening or PGS. PGS is also sometimes referred to as “24-chromosome screening.” Another term often used to describe PGS is “PGT-A,” which stands for “preimplantation genetic testing for aneuploidy.”
How is PGS/PGD done?
The first step in a PGS/PGD cycle is to obtain embryos. Usually, we create embryos by doing an in vitro fertilization (IVF) cycle with intracytoplasmic sperm injection (ICSI). Additionally, if a couple already has cryopreserved (frozen) embryos from a previous IVF with ICSI cycle, those embryo(s) can be used in a PGD/PGS cycle. Once we obtain the embryos, we biopsy them. In other words, we remove several cells of the embryo(s).
In most cases, after we biopsy the embryo(s), they are cryopreserved. The cells are then sent to a PGS/PGD lab where they are tested. The specific tests performed on the cells and how that testing is accomplished is determined on a case-by-case basis, depending on the needs of the individual patient. Among other factors, we look at the most cost-effective options to meet our individual patients’ needs. Once the test results are obtained, the embryo(s) with normal test results are thawed and transferred to the patient’s uterus.
Who can benefit from PGS/PGD?
Patients who may benefit from PGD include anyone with a known genetic disease or mutation that may lead to disease. Determining who may benefit from PGS is more controversial. Patients with recurrent pregnancy loss, older patients who are at an increased risk for a genetically abnormal child, and patients with a known chromosomal translocation, may benefit from PGS. In addition, embryos that are screened with PGS and found to be healthy have a higher implantation rate than unscreened embryos. Therefore, some patients opt for PGS in order to maximize their chances of success. Since the implantation rates of screened embryos are higher, using PGS, we can transfer fewer embryos and still have a high probability of success. This is a very appealing option for many patients because transferring fewer embryos minimizes the chance of multiple pregnancies. Therefore, some experts advocate using PGS for patients who desire a single embryo transfer. Ultimately, the decision of whether or not to pursue PGS/PGD is an individual one that must be made with a specialized health care provider.
Can PGS/PGD be used to tell the sex of an embryo?
Yes, PGS/PGD can be used to determine the sex of an embryo. This can be particularly helpful because some diseases only occur in male or female children. In these situations, PGS/PGD technology is used to select a male or female embryo in order to minimize the chance of having a child affected by a specific disease. Whether or not we should use the technology to determine sex outside of this indication is more controversial. Anyone who is considering sex selection should discuss the option with a knowledgable health care provider to ensure that they understand the benefits and limitations of the technology.
How much does PGS/PGD cost?
The cost of PGS/PGD can vary significantly depending on what testing is required. The good news is that in Illinois, depending on the indication, insurance may cover the cost of the testing. If the testing is not covered, as a general estimate, it runs between $3,000 and $5,000.
A preimplantation genetic diagnosis can tell you a lot about the potential health of an embryo. Call Advanced Reproductive Center at 312.485.4847 today to learn more about how such a procedure can help you.