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.