Preimplantation genetic diagnosis (PGD) is often performed as part of the in vitro fertilization (IVF) process. The procedure is completed prior to implantation to help identify possible genetic defects within embryos. With the use of PGD, couples have the option to identify and prevent certain genetic disorders and diseases from being passed down to their child. Preimplantation genetic diagnosis is best suited for parents who are known carriers of certain single gene disorders, such as cystic fibrosis or hemophilia.
How Does PGD Work?
Often times, diseases develop as a result of specific gene mutations in DNA. These mutations can be detected through PGD. The process begins with normal IVF which involves egg retrieval and in-lab fertilization. If successful, embryos will divide into multiple cells within three to five days. Once the embryos reach blastocyst stage, cells are removed from the outer layer of the embryo and sent to a special lab to test for certain genetic abnormalities.
After PGD has identified which embryos are free of genetic problems, the healthy embryos are placed in the uterus through the normal IVF procedure. The couple must then wait for implantation to occur, followed by a positive pregnancy test. If additional embryos are found to have no genetic problems, they can be kept frozen for use later if desired. Embryos that are found to have gene abnormalities are destroyed.
Who Is a Good Candidate for PGD?
Any couple who is at risk for passing on a genetic condition or disease to their child may be good candidates for preimplantation genetic diagnosis. This includes carriers of single gene disorders, carriers of sex-linked genetic disorders, individuals with chromosomal disorders, women who have experienced recurrent pregnancy loss, women who have had more than one failed fertility treatment, and women over age 35.
PGD can be successfully used to test for over 100 different genetic conditions. With this type of genetic testing, couples are able to choose if they wish to continue with the pregnancy as the procedure is performed before implantation occurs. This can provide peace of mind for at-risk couples trying to conceive.