Preimplantation Genetic Diagnosis (PGD) and Preimplantation Genetic Screening (PGS)

Preimplantation genetic diagnosis and preimplantation genetic screening for embryos

Preimplantation genetic diagnosis determines which embryos carry or are affected by specific genetic diseases such as cystic fibrosis or Tay Sachs disease. If you or your partner, or both of you, are carriers of a specific genetic disease, preimplantation genetic diagnosis offers a way to reduce your chances of having a child with that disease. Your embryos are tested before they're transferred to the uterus during in vitro fertilization. This way, only those without the genetic problem are transferred.

Preimplantation genetic screening is a test done to determine if an embryo has normal chromosomes. After in vitro fertilization, but before transfer to the uterus, preimplantation genetic screening is done to check for the correct number of chromosomes.

The wrong number of chromosomes could indicate a condition such as Down syndrome or another chromosomal condition that may lead to a miscarriage. After preimplantation genetic screening, only those embryos with the correct number of chromosomes are transferred to the uterus.

Preimplantation genetic screening can also show which embryos are male and which are female, so you're able to choose the gender of the embryos you want to implant, if you wish.

Other advanced screening techniques for embryos

Along with preimplantation genetic diagnosis and preimplantation genetic screening, Main Line Health offers other advanced ways to help make sure you have a healthy pregnancy, including:

• Blastocyst biopsy with aCGH – This test measures the mitochondrial DNA activity of each embryo to help learn which embryos have the best chance of implanting.
• EEVA time lapse imaging – This test helps predict how well an embryo will do in the womb based on how well it has done during the first few days of its development.