What is 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 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
A PGS Success Story
Louis and Helen share how PGS helped realize their dreams of having a baby after 6 years of unexplained infertility.
Improving IVF Success Rates by Better Embryo Selection
Simon Fishel describes how PGS enables the selection of embryos for transfer that are most likely to be free of chromosomal problems.
How Preimplantation Genetic Screening Works
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
The Advantages of PGS
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:
- Mitigates several reproductive challenges associated with maternal age4
- Leads to greater implantation rates and improved IVF outcomes5
- Enables single embryo transfers with higher chance of success, reducing multiple births and the complications that can result from it6,7
Improving IVF success with advanced PGS
A quick overview of IVF statistics.
Significantly Higher Rate of Pregnancy May Be Possible with PGS
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)
Screening Embryos for Aneuploidy with PGS
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.
Leading the way: advantages to adding PGS
Watch Dr. Angeline Beltsos to learn more about the advantages of preimplantation genetic screening.
References
- Centers for Disease Control and Prevention.Org Website Accessed March 11, 2016.
- Scott RT, Ferry K, Su J, Tao X, Scott K, Treff NR. Comprehensive chromosome screening is highly predictive of the reproductive potential of human embryos: a prospective, blinded, nonselection study. Fertil Steril. 2012;97(4):870-875.
- Ata B, Kaplan B, Danzer H, et al. Array CGH analysis shows that aneuploidy is not related to the number of embryos generated. Reprod Biomed Online. 2012;24:614–620.
- Harton GL, Munne S, Surrey M, et al. Diminished effect of maternal age on implantation after preimplantation genetic diagnosis with array comparative genomic hybridization. Fertil Steril. 2013;100(6):1695–1703.
- Yang Z, Liu J, Collins GS, Salem SA, Liu X, et al. (2012) Selection of single blastocysts for fresh transfer via standard morphology assessment alone and with array CGH for good prognosis patients: results from a randomised pilot study. Mol Cytogenet 5: 24.
- Forman EJ, Hong KH, Ferry KM, et al. In vitro fertilization with single euploid blastocyst transfer: a randomized controlled trial. Fertil Steril. 2013;100(1):100–107.
- Grifo JA, Hodes-Wertz B, Lee HL, Amperloquio E, Clarke-Williams M, Adler A. Single thawed euploid embryo transfer improves IVF pregnancy, miscarriage, and multiple gestation outcomes and has similar implantation rates as egg donation. J Assist Reprod Genet. 2013;30(2):259–264.