Pre-implantation Genetic Diagnosis (PGD) and Preimplantation Genetic Screening (PGS) are terms used to describe the process by which an embryo can be screened for genetic disorders/chromosome number before transferring the embryos back to the uterus.
If you are considering IVF with PGD or PGS, it is important to know that both are done on embryos as part of an in vitro fertilization (IVF) cycle. This requires that the embryos be biopsied on day 5 or 6 and subsequently frozen until results have been obtained. The embryo biopsy is performed from the part of the embryo that forms the placenta (trophectoderm or outer cell mass). Typically results are available within 7-10 days, and the frozen embryo transfer can occur within the next month.
What is PGD?
PGD tests embryos for a specific genetic disease. This is usually done when there is a family history of a certain disease and/or the couple is aware of being a carrier of a certain genetic disorder. Examples of single gene disorders for which PGD can test are:
Spinal Muscular Atrophy
Sickle Cell Anemia
What is PGS?
PGS screens the embryos for chromosomal numbers. An embryo should have 46 chromosomes; an abnormal number of chromosomes (called aneuploidy) can cause failure of implantation, genetic disorders, and miscarriage.
PGS is routinely used for infertile couples, especially those struggling with common causes of infertility, such as advanced maternal age, repeated IVF failure, recurrent miscarriages, or a history of abnormal pregnancies.
In patients carrying disease-causing single gene mutations, it is possible (and recommended) to test for both the single gene defects as well as aneuploidy because both can be tested for at the same time.
The advantages of genetic testing include increased chances of pregnancy, decreased chances of multiple pregnancy, decreased chances of pregnancy loss, and the ability to avoid undesired genetic diseases.
To see a Board Certified physician who routinely offers PGS to IVF patients and has expertise in PGD, make an appointment at one of InVia's Chicagoland locations. Prior to making any decision about genetic testing, your physician will review you and your partner’s history and develop a treatment plan tailored to your specific needs.
Liza has been an embryologist at InVia Fertility Specialists since 2002. She completed her studies, first in animal science at Southern Illinois University, followed by clinical embryology/reproductive genetics at Eastern Virginia Medical School. Her interests include reproductive genetics, fertility preservation, and mitochondrial function in the human oocyte. She loves being a part of helping others achieve and experience the joy of becoming a parent. Seeing the end result .your baby.makes all the hours in the lab worth it!