USC Fertility

How Does PGT-A (Formerly PGS) Work?

How does PGT-A work? Exploring this question

Many patients ask, “How does PGT-A work?” This form of testing was once called PGS, and our team performs it as part of an IVF cycle. If you opt for PGT-A, you can expect to undergo the following steps.

  • First, the female partner will medications to stimulate the growth of multiple eggs.
  • A fertility doctor will then retrieve the eggs during an office procedure.
  • Laboratory professionals will fertilize the eggs with sperm using ICSI.
  • The embryos will develop in the embryology laboratory over the course of 5-6 days.

Once the embryos reach the blastocyst stage, we will remove a few cells from the outer layer of the embryo (a trophectoderm biopsy). Our team sends these cells to a special laboratory to undergo testing for chromosomal abnormalities, and we freeze the embryos.

When we receive the results, we will transfer the best quality embryo(s) to the uterus. If additional chromosomally normal embryos are available, they can remain frozen for a future transfer.

“How does PGT-A work?” Answers to other important questions

Aside from answering the query, “How does PGT-A work?” it’s important to explore some other questions.

Can PGT-A and PGT-M occur at the same time? Yes. Embryos can undergo both screening for in addition to heritable genetic diseases and screening for chromosomal abnormalities.

When does the embryo biopsy occur?

We allow the embryos to develop to the blastocyst stage at Day 5 or later when the embryo has 200 or more cells. This makes the biopsy safer. We remove the cells from the outer layer of embryo, without harming the cells that will become the baby.

Do I still need to have genetic testing during the pregnancy?

Yes. You still need genetic testing during pregnancy. Preimplantation genetic testing does not replace prenatal testing, such as cell-free fetal DNA testing, chorionic villus sampling (CVS) or amniocentesis. Therefore, prenatal testing is still remains the standard of care.

Is PGT-A safe?

PGT-A was introduced in 1990, and the procedure does not appear to affect the development of the embryo and subsequent pregnancy or the child once it is born. However, more follow up studies are needed.

Contact us if you have more questions or would like to schedule an appointment. We are always happy to answer questions like, “How does PGT-A work.”