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 aneuploidy — embryos with an abnormal number of chromosomes.1,2 Aneuploidy can occur in any embryo; however, the chances increase with maternal age.3,4
Following ovarian stimulation and egg retrieval, a single or a few cells are biopsied from the embryo.
Embryos are screened for aneuploidy.
Those most likely to be euploid are either transferred to the uterus or frozen for future use.
The chances of IVF success are improved.4,6,7
Selectively transferring embryos most likely to have a normal number of chromosomes (euploid) is important in reducing miscarriage rates and improving IVF success rates.4,5,6,7 Preimplantation genetic screening has the following benefits:
The pregnancy rate shown for embryos analyzed using preimplantation genetic screening and morphology is 69.1%, much higher than the 41.7% achieved using morphology screening alone.5
Pilot study of young, good prognosis patients (age < 35, first-time IVF, no history of prior miscarriage, n = 103)
After oocytes are retrieved from a woman and fertilized during an IVF cycle, a single or few cells are removed from the embryo through a biopsy. The cell or cells are analyzed for their aneuploidy status by screening all 24 chromosomes.
Preimplantation genetic screening can be performed using next-generation sequencing (NGS) or an array-based method.