For couples who pursue in vitro fertilization (IVF), Spectrum Preimplantation Genetic Screening (PGS) offers embryo screening to improve the chance of achieving a healthy pregnancy. PGS is used to identify embryo(s) that have extra or missing chromosomes, also called aneuploidy. Screening for the number of chromosomes allows for the selection and transfer of embryo(s) most likely to have the correct chromosome number. These embryos are more likely to implant and are much less likely to miscarry.
While any couples can have an embryo with aneuploidy, couples at higher risk and couples who are considering single embryo transfer (SET) should ask their doctor about Spectrum.
Discuss PGS with your doctor, especially if you have one or more of the following indications:
PGS requires embryo biopsy, the removal of either a single or a small number of cells from a growing embryo. The biopsy procedure can be performed on day 3 after egg retrieval, or more commonly, on day 5 or 6 when embryos reach the blastocyst stage of development.
Humans generally have 23 pairs of chromosomes, identified as chromosome numbers 1-22, with the 23rd pair being the sex chromosomes, XX (female) or XY (male). Aneuploidy is when too many or too few chromosomes are present. Most of the time, aneuploidy occurs by chance during the formation of the egg or sperm, or during the early development of the embryo. Embryos with aneuploidy usually either fail to implant or miscarry – in fact, the majority of miscarriages are due to aneuploidy.
Certain forms of aneuploidy can be found in live born babies and typically cause varying degrees of intellectual disability and birth defects. For example, Down syndrome, a common form of intellectual disability, is caused by an extra copy of chromosome number 21.
Any couple can have an embryo with aneuploidy, but the chances increase with the age of the mother – for day 5/6 embryos, this ranges from approximately 32% in women under age 35 to over 75% in women 40 and older. Research also suggests that couples that have had multiple miscarriages, previously failed IVF cycles, or a prior pregnancy with a chromosome problem are at increased risk of having embryos with aneuploidy.
When considering single embryo transfer, the ability to choose an embryo with normal chromosome results improves the chances of implantation and a healthy pregnancy.