Pre-implantation Genetic Testing: Understanding Embryo Screening

seated researchers in a lab looking at computers

Pre-implantation Genetic Testing (PGT) provides a proactive approach to fertility care. It enables couples and single individuals using assisted reproductive technology like IVF (in vitro fertilization) to test their embryos for genetic abnormalities before pregnancy. PGT allows the parent/s to understand the viability of their embryos. We asked Dr. Angela Q. Leung, Reproductive Endocrinologist at RMA of NJ, to help break the process down in detail.

Are there different types of pre-implantation genetic testing?

Yes, there are primarily three different types of PGT.

  • PGT for Monogenic/Single Gene Defects (PGT-M)
  • PGT for Chromosomal Structural Rearrangements (PGT-SR)
  • PGT for Aneuploidies (PGT-A)

The process of pre-implantation genetic testing (PGT)

During an IVF cycle, parents can elect to have pre-implantation genetic testing performed as part of their treatment. In an IVF cycle, eggs are retrieved from a female patient and combined with sperm in a lab (usually through a technique called intracytoplasmic sperm injection or ICSI) to form an embryo. Once the embryo reaches the blastocyst stage (day 5-7 of development), a sample of cells is biopsied and then analyzed in a genetics lab. Genetic testing evaluates the sample for chromosomal abnormalities, specific mutations, or structural rearrangements. The results from the test are used to select the healthiest embryo/s to implant in the uterus.

What are the benefits of having my embryos tested?

PGT offers several advantages. The main advantage is that your physician can select the healthiest embryos to transfer during an IVF cycle, and the likelihood of successful implantation and a live birth increase. PGT decreases the probability of miscarriage caused by chromosomal abnormalities and the risk of having a child born with certain genetic conditions. Another advantage is being able to select the gender of your child since the sex chromosomes are identified as a result of the testing.

Can PGT harm my embryos?

There is minimal risk of damage to the embryos during the biopsy necessary to perform the genetic testing. PGT testing is considered a safe and highly recommended procedure for all fertility patients.

Does PGT increase my chances of achieving pregnancy?

Yes, PGT can potentially increase the chances of establishing a healthy pregnancy. PGT helps ensure that a chromosomally normal (euploid) embryo is transferred during an IVF cycle, thus increasing the procedure’s success rate. However, it’s important to note that several factors contribute to a successful overall pregnancy, such as the age and general health of the mother.


The use of pre-implantation genetic testing in the field of reproductive medicine has dramatically improved IVF success rates over the years. Many Reproductive Endocrinologists (fertility specialists) recommend genetic testing of embryos, especially for women of advanced reproductive age, couples experiencing recurrent miscarriages or at risk of passing along known genetic diseases. PGT has already helped a multitude of people have healthy babies. As we understand more about embryo health, the applications and benefits of pre-implantation testing will continue to expand.