During an IVF treatment, sometimes genetic testing is performed to make sure the embryo does not contain genetic abnormalities before finally transferring it into the womb.
Learn more about both how our PGT-A (Preimplantation Genetic Testing for aneuploidy) solution may improve your chance of a successful pregnancy and how our PGT-M (Preimplantation Genetic Testing for Monogenic Disease) can help prevent the inheritance of a genetic disorder to your children.
During the IVF process, PGT-A screens embryos to find those most likely to have the correct number of chromosomes. This may help to increase the chances of successful implantation and an ongoing pregnancy while decreasing the chance of miscarriage.4,6-8 PGT-A can also help you and your clinician decide about single embryo transfer, which reduces the chance of a high-risk multiple pregnancy.5,6
Chromosomes are the structures inside our cells that carry our genetic makeup, or DNA. Human cells typically have a total of 46 chromosomes. 23 chromosomes come from the mother, and 23 chromosomes come from the father.1
When an embryo has an incorrect number of chromosomes, it is referred to as aneuploidy (an-yu-ploy-dee). An extra copy of a chromosome is called a trisomy (tri-so-mee), and a missing copy of a chromosome is called a monosomy (mon-o-so-mee).1
Aneuploidy can occur in embryos in women of any age. But the chances of aneuploidy increase as the mother’s age increases. On average, approximately half of embryos in an IVF cycle are aneuploid, although this number may be higher in women of increased maternal age.2-4
Embryos with aneuploidy often fail to implant, and those that do implant often result in miscarriage.9,10 A pregnancy with aneuploidy can sometimes lead to a live birth.2 However, in most cases, these babies will have physical abnormalities and/or intellectual disabilities. The most common aneuploidy in live born babies is trisomy 21, also known as Down syndrome.11
1. Following ovarian stimulation, egg retrieval, and fertilization, a single or a few cells are biopsied from the embryo.
2. Embryos are screened for aneuploidy.
3. The embryos most likely to be euploid (ie, having the correct number of chromosomes) are either transferred to the uterus or frozen for future use.
4. The chances of IVF success may be improved.
If you’ve struggled to get pregnant or experienced an early miscarriage following in vitro fertilisation (IVF), our Preimplantation Genetic Testing for aneuploidy (PGT-A) solution may be able to help. Talk to your clinician to see if PGT-A is right for you.
PGT-M (Preimplantation Genetic Testing for Monogenic Disease) assesses embryos to help prevent the transmission of an inherited genetic disorder to your children. Using our Karyomapping solution to analyse DNA, your IVF professional gains insight into the inheritance of single-gene defects.
You may know that you are a carrier of a genetic disorder because you already have an affected child or you may be aware of a family history or the disorders and have had your DNA tested.
Karyomapping is a technique that allows couples who are known to be carriers or affected with a single gene disorder to avoid passing on that disorder to their offspring. The technique works by screening the embryos for the disorder before implantation in the womb (uterus) - a technique called Preimplantation Genetic Testing for Monogenic Disease (PGT-M).
Using PGT-M greatly reduces the chance that the fetus will be affected by the genetic disorders and consequently it much less likely that termination of pregnancy will need to considered, or that an affected child will be born.
In order to carry out PGT-M, in vitro fertilisation is essential. This process involves collecting several eggs from the ovaries and fertilising them outside the body (in vitro), to produce several embryos. Each of the embryos can then be tested to find out which are suitable for transfer.
Only the embryos that are predicted to be free of the genetic condition can be transferred to the uterus, and consequently any pregnancy begins has a low risk of being affected by the disorder.
A blood sample is taken from the father, the mother and a close relative of known disease status (affected, unaffected or carrier). In most cases the relative tested is a child of the couple. The relative is referred to as the “reference”.
Karyomapping looks at the chromosomes, the long rod-like structures that are found in cells and contain the genes. Karyomapping examines the chromosomes of the mother, father and the reference at approximately 300,000 different points and finds a DNA fingerprint unique to the chromosome that carries the defective gene. It is possible to test embryos produced using IVF for this fingerprint, revealing that those that have inherited the affected chromosome.
If the fingerprint characteristic of the chromosome carrying the defective gene is not defected,then it can inferred that the embryo has inherited normal copies of the gene and is therefore likely to be free of the disorder. Embryos of this type are good candidate for transfer to the mother’s uterus (womb).
Historically PGT-M tests had to be tailor made for each couple. The required weeks or months of work by highly skilled scientists meaning that costs were high and therefore was often a long wait before IVF treatment could begin. By contrast PGT-M using karyomapping provides a test of almost any know single gene disorder with a rapid turnaround time. Since karyomapping uses thousands of markets per chromosome it is likely to more accurate than current tests.
Karyomapping is available in a number of leading fertility clinics worldwide. If you are considering this type of treatment and would like to find out whether it is available at your chosen clinic, please enquire with them directly as its important that each couple have their individual circumstances assessed appropriately by a clinician.
A retrieval needle, called Sense, gives you a fast and precise egg collection that retrieves the maximal amount of undamaged eggs without complications.Learn more
Embryologists are able to monitor your embryos' development without removing them from the safe environment of the incubator.Learn more
EmbryoGlue is a medium that closely resembles the environment in the womb at the time of implantation, which can support implantation even more.Learn more
1. Gardner RJM, Sutherland GR, Schaffer LG. Chromosome Abnormalities and Genetic Counseling. 4th ed. New York, NY: Oxford University Press; 2012.
2. Liu J, Wang W, Sun X, et al. DNA microarray reveals that high proportions of human blastocysts from women of advanced maternal age are aneuploid and mosaic. Biol Reprod. 2012;87(6):148.
3. 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(6):614-620.
4. Harton GL, Munné S, Surrey M, et al; for the PGD Practitioners Group. Diminished effect of maternal age on implantation after preimplantation genetic diagnosis with array comparative genetic hybridization. Fertil Steril. 2013;100(6):1695-1703.
5. American College of Obstetricians and Gynecologists. ACOG Practice Bulletin No. 144: Multifetal gestations: twin, triplet, and higher-order multifetal pregnancies. Obstet Gynecol. 2014;123(5):1118-1132.
6. 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.
7. Yang Z, Liu J, Collins GS, et al. Selection of single blastocysts for fresh transfer via standard morphology assessment alone and with array CGH for good prognosis IVF patients: results from a randomized pilot study. Mol Cytogenet. 2012;5(1):24.
8. 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.
9. Simpson JL. Causes of fetal wastage. Clin Obstet Gynecol. 2007;50(1):10-30.
10. Scott RT Jr, 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.
11. Jones KL, Jones MC, del Campo M. Smith’s Recognizable Patterns of Human Malformation. 7th ed. Philadelphia, PA: Elsevier Saunders; 2013