Embryos created from In Vitro Fertilization (IVF) cycles can be genetically tested before being returned to a woman’s uterus for implantation.
What is PGT?
Preimplantation Genetic Testing (PGT) refers to innovative technologies which screen embryos for certain genetic abnormalities. There are three types of PGT:
Preimplantation Genetic Testing for Aneuploidy (PGT-A) refers to screening embryos for chromosomal disorders. Chromosomal disorders refer to genetic conditions in which an embryo has an extra or a missing chromosome. Embryos that have extra or missing chromosomes are referred to as “aneuploid” embryos. An embryo should have 2 copies of every chromosome, one provided from the egg, and one from the sperm. If an embryo has 1 copy or 3 copies of a chromosome, it is considered aneuploid.
Who should consider PGT-A:
PGT-A screening is an option for anyone undergoing IVF because chromosomal disorders occur randomly. PGT-A is often recommended for patients with unexplained infertility, recurrent miscarriages, unsuccessful IVF cycles, and advanced reproductive age.
Women of advanced reproductive age (over 35) are at a higher risk of producing aneuploid embryos. A woman is born with all the eggs she will ever have. Over time, the chromosomes within the egg are less likely to divide properly, resulting in cells with too many or too few chromosomes. Aneuploidy is also believed to be a major reason for the decrease of fertility with age. Prior to attempting a pregnancy, women in this age group may wish to talk with their physician or a genetic counselor about their chances of having a child with a chromosomal disorder and how PGT-A may be able to help.
PGT-A helps aid in the selection of a single embryo for transfer and decreases the risk of multiple birth.
Preimplantation Genetic Testing for Structural Rearrangements (PGT-SR) refers to screening embryos for inherited chromosomal rearrangements called translocations and inversions.
Who should consider PGT-SR:
PGT-SR is only an option for individuals who have a known chromosomal translocation or inversion in the family.
Structural chromosome rearrangements are an inherited genetic cause of recurrent pregnancy loss. If you have had a history of multiple miscarriages, talk to your doctor to see if you need further analysis and if PGT-SR is an option for you.
Preimplantation Genetic Testing for Monogenic/Single Gene Disorders (PGT-M) refers to screening embryos for inherited genetic conditions such as Cystic Fibrosis, Sickle Cell Disease, Huntington Disease and Hereditary Breast and Ovarian Cancer Syndrome (HBOC).
Who should consider PGT-M:
PGT-M is only an option for individuals who have a personal or family history of genetic diseases or those that are found to be at risk of having a child with a genetic disease through preconception genetic screening (i.e. carrier screening).
PGT-M is more complicated than PGT-A and PGT-SR. The PGT-M test development process takes a minimum of 4-6 months.
Our in-house genetic counselor is available to discuss all PGT options to help determine what is right for you.