Preimplantation Genetic Screening (PGS)
Preimplantation genetic screening (PGS) determines the chromosomal status of an embryo by screening all 23 chromosome pairs prior to transfer in an IVF cycle. PGS may be appropriate for couples pursuing IVF due to a history of infertility or recurrent pregnancy loss because a major cause of IVF failure is aneuploid embryos with an abnormal number of chromosomes. The chances of aneuploidy increase with maternal age.
Preimplantation Genetic Diagnosis (PGD)
Preimplantation genetic diagnosis (PGD) enables people with an inheritable condition in their family to avoid passing it on to their children. It involves checking the genes and/or chromosomes of embryos created through IVF. The evaluation process takes at least 7 days. Only the selected healthy embryos are placed in the uterus of the mother. The remaining embryos are kept frozen for future use. PGD involves the testing of 100 different genetic conditions.