PGT: Preimplantation Genetic Testing: Definition & Explanation
Preimplantation genetic testing, or PGT, is a procedure used during IVF to screen embryos for either specific known genetic disorders carried by the parents (PGT-M) or for aneuploidy, or abnormal numbers of chromosomes (PGT-A). Several days after fertilization occurs during IVF treatment, 5-8 cells are removed by an embryologist from the outer trophectoderm of a high-quality blastocyst and screened for specific disorders.
When Is PGT Recommended?
PGT-M is ideal for couples or individuals concerned with passing a genetic disease or chromosomal abnormality on to their children (a “monogenic” disorder, such as cystic fibrosis, BRCA, or Huntington’s disease).
PGT-A is recommended based on a variety of patient factors, including age, ovarian reserve, and infertility diagnosis. For example, patients at higher risk for aneuploidy (those over 35) or with a history of recurrent miscarriages may be good candidates for PGT-A.
PGT — Getting Started
If you believe that IVF with PGT is right for you, the first step toward getting IVF treatment is to schedule a consultation. During your appointment, you will meet with one of our board-certified fertility specialists, who will help you craft an affordable and effective fertility treatment plan. Our financial counselors will also be available to walk you through our payment plans & insurance options.
PGT — Related Topics
Preimplantation genetic testing is commonly used in combination with IVF. Learn more about other advanced IVF procedures, including:
View more infertility treatments
The PGT Process
IVF can be a challenging step on your journey to parenthood. In order to help you understand what is involved in IVF and PGT, we have provided a step-by-step breakdown of the preimplantation genetic testing process:
- Step 1 — IVF Preparation: Fertility medications are prescribed to stimulate the ovaries to grow numerous eggs. The eggs are then retrieved from a woman’s ovaries through a quick, minimally invasive procedure.
- Step 2 — Laboratory: The eggs and semen are then prepared for IVF in the laboratory. Eggs are identified and examined for maturity while the semen is prepared through a process called sperm washing.
- Step 3 — Fertilization: The eggs may be fertilized with either insemination (in which sperm are placed with the egg in a dish) or with intracytoplasmic sperm injection (ICSI), used most commonly for couples with male factor infertility. In ICSI, a single sperm is isolated by a hollow glass needle and injected into the center of an egg. Resulting embryos are incubated together for 5 to 7 days until the embryo becomes a blastocyst, which is made up of hundreds of cells.
- Step 4 — PGT: Five to eight of the cells from the embryo’s trophectoderm (the cells that will eventually form the placenta) are removed by an experienced embryologist to be tested by a genetics laboratory for either aneuploidy, a specific gene, or both. “Normal” embryos are identified, and the provider and patient receive a report with this information. At our clinic, we do not receive information regarding the sex of each embryo unless medically indicated.
- Step 5 — Follow-Up and Embryo Transfer: You will meet with your infertility doctor to discuss your results and plan your frozen embryo cycle. These cycles can be done with a natural cycle or with medications to prepare the uterine lining. This preparation can often be started right away! After your embryo transfer, you will have a blood pregnancy test about nine days later. With expert treatment, attentive care and just a little luck, you will have a positive result. Then it is time to start planning for the new addition to your family!
Facts about PGT: Preimplantation Genetic Testing
- PGT-A is also referred to as embryo screening.
- PGT-M can detect genetic defects such as Huntington’s disease, Tay-Sachs disease, cystic fibrosis and much more.