Preimplantation genetic testing (PGT)

Genetic or chromosomal problems in an embryo can cause implantation issues, miscarriage, or birth defects. Preimplantation genetic testing (PGT) screens an embryo for genetic or chromosomal abnormalities before we place it in your uterus.

A normal embryo has 46 chromosomes (half from the sperm and half from the egg) and the sex chromosomes XX (female) or XY (male). Chromosomes contain genes that determine what you look like and how your body works. Occasionally, genes have mutations (abnormal changes) or chromosomes might be missing, duplicated, or in the wrong location.

PGT, sometimes called embryo screening, is an optional test you may choose to do during in vitro fertilization (IVF). The test happens after fertilization but before implantation. The results of PGT can help individuals and couples undergoing IVF make informed decisions as they select embryos for transfer.

The test isn't right for everyone receiving IVF treatments. Our IVF and assisted reproduction and infertility care specialists carefully evaluate your personal and family medical history. We discuss the results with you and help you decide if PGT is best for your unique situation.

The cost depends on how many embryos we test. Most insurance providers don't cover PGT, so we understand the expense can be difficult for individuals and couples. Our Penn Medicine financial advocates connect you to resources and help you manage the cost of PGT and other fertility treatments.

Embryo transfers most commonly fail because of a genetic abnormality. Your provider or a genetic counselor will discuss if PGT is right for you and which type of test we recommend. PGT helps you and your doctor select an embryo that has normal chromosomes, which reduces your chance of an unsuccessful IVF cycle or miscarriage.

You may be eligible for embryo screening if you have:

• A previous unsuccessful IVF cycle
• Advanced maternal age (older than 35)
• Given birth to a child with a chromosomal abnormality or genetic disease
• Multiple unexplained miscarriages (recurrent pregnancy loss)
• Unexplained female infertility

We may also recommend PGT if you or your partner have a:

• History of an inherited genetic disorder or are a known carrier of a gene mutation
• Chromosomal rearrangement

The process is the same for all three PGT types. You go through a regular IVF cycle and egg retrieval procedure with your fertility specialist. Our skilled embryologist fertilizes the eggs with your partner's or donor's sperm in our on-site lab. We carefully monitor the embryos' development for several days.

Once the embryos are developed enough—typically by day 5 or 6—we biopsy a small number of cells from each embryo. We remove cells from the part of the embryos that develop into the placenta. The section of the embryos that develop into a baby is undisturbed by the biopsy.

We freeze your embryos while we wait for PGT test results, which may take a few weeks. Your doctor reviews the test results with you and selects a healthy embryo to transfer to your uterus. Your other embryos with normal PGT results can stay frozen and safely stored in our secure laboratory for a future embryo transfer.

There’s no known risk to babies born after preimplantation genetic testing. The biopsy process can damage the embryo and cause unsuccessful implantation, though it's rare.

There’s a slight chance PGT results can be inaccurate or inconclusive, meaning we can't determine clear results. We recommend prenatal testing to confirm test results once you're pregnant.

Our embryologists perform preimplantation genetic testing with care and excellence. We understand that PGT results inform your family's future, and our laboratory team has the technical skills and equipment to ensure top-quality testing.

We’re here to discuss the risks, benefits, and costs of PGT with you so you can make an informed, confident decision.