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.
