FAQ Genetics

Studies on fertility treatments have shown that a significant proportion of embryos produced during in vitro fertilization (IVF) are incapable of forming a healthy pregnancy. One of the primary reasons some embryos fail to produce a baby is the presence of a chromosomal abnormality (see Chromosomes and Aneuploidy for more information).In most cases, embryos with an abnormal number of chromosomes cannot implant in the uterus or miscarry during the first trimester of pregnancy. Unfortunately, chromosomally abnormal embryos are usually indistinguishable from their normal counterparts using the routine microscopic (morphological) assessments conducted in IVF laboratories. As a result, embryologists may unintentionally select these abnormal embryos for transfer.

By testing embryos for chromosomal abnormalities, the chances of achieving a healthy pregnancy are increased, while the risks of miscarriage and aneuploidy-related conception are decreased.

Preimplantation Genetic Testing (PGT) is a powerful tool used during IVF to screen embryos for genetic and chromosomal conditions, offering a higher chance of a successful pregnancy. The ideal candidates for PGT vary depending on the type of test required: PGT-A (for Aneuploidy) and PGT-M (for Monogenic Disorders).

PGT-A (Preimplantation Genetic Testing for Aneuploidy)

PGT-A is used to screen for chromosomal abnormalities, such as extra or missing chromosomes. Most cases of early miscarriage can be attributed to such chromosomal issues. With PGT-A, only chromosomally normal embryos are transferred to the uterus, significantly reducing the risk of miscarriage in the first and second trimesters.

Ideal candidates for PGT-A include:

• Women of advanced maternal age.
• Couples with chromosomal translocations that may cause implantation failure or recurrent miscarriage.
• Couples with a history of recurrent miscarriage or mental/physical health issues in offspring.
• Couples with repeated IVF failure.
• Male partners with severe infertility due to medical factors.

PGT-A helps reduce the risk of chromosomal abnormalities being passed on and minimizes the chances of delayed pregnancy.

PGT-M (Preimplantation Genetic Testing for Monogenic Disorders)

PGT-M is recommended when one or both parents carry a known genetic mutation that could be passed on to their children. This test screens embryos for specific inherited conditions.

Ideal candidates for PGT-M include:

• Couples with a family history of X-linked disorders, such as hemophilia, Fragile X syndrome, and neuromuscular dystrophy. (There is a 25% risk of passing the condition to male embryos.)
• Carriers of autosomal recessive genetic diseases, such as cystic fibrosis, Tay-Sachs disease, sickle cell anemia, thalassemia, and spinal muscular atrophy. (There is a 25% risk of passing the condition to the embryo.)
• Carriers of autosomal dominant genetic diseases, such as Huntington’s disease, neurofibromatosis type 1, and Marfan syndrome. (There is a 50% risk of passing the condition to the embryo.)

PGT-M allows couples to avoid passing on inherited genetic conditions and helps in building a healthy family.