Pre-implantation Genetic Screening
One significant development in assisted reproductive technology in the last 25 years is our ability to remove cel...
One significant development in assisted reproductive technology in the last 25 years is our ability to remove cells (biopsy) from a developing embryo and perform genetic testing. This procedure is termed Pre-implantation Genetic Screening (PGS) and also commonly referred to as embryo screening. PGS is an established treatment option to improve your chances of conceiving a healthy baby by selecting an embryo that has the highest chance of resulting in an ongoing pregnancy. Our internationally recognised PGS program at Melbourne IVF continues to be a leader in the development of PGS testing in Australia. In 2010, we introduced 24Sure Array CGH technology which was originally pioneered by our specialist team in the late 1990’s. Today it continues to offer the most scientifically advanced technology to screen embryos for chromosomal abnormalities.
Figure 1: Cells being removed during Day 5 biopsy
What is Pre-implantation Genetic Screening? In PGS we screen an embryo for the correct number of chromosomes. Chromosomes are important because they carry the instructions, in the form of genes, which determine how we develop and function. An important factor in determining if an embryo will result in an ongoing pregnancy is that it contains the correct number of chromosomes. It is common for embryos to contain an incorrect number of chromosomes, regardless of your personal health and reproductive history. When this happens, the most likely outcome is that the embryo will not implant (lead to a negative pregnancy test) or will implant but then miscarry. Less commonly, this can lead to the birth of a baby with a chromosome condition such as Down syndrome.
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The frequency of these chromosome errors increases with maternal age. We know that approximately 30% of embryos from women aged 30 will have the incorrect number of chromosomes. This proportion increases to 80% when the woman is aged 40, due to the ageing process that occurs in the egg. At 30 years of age, 1 in 6 pregnancies end in miscarriage. At 40 years, this figure will rise to 1 in 3 pregnancies.
What is involved in Pre-implantation Genetic Screening? Cells are removed from an embryo, usually five to six days after egg collection, in a process known as an embryo biopsy. These biopsied cells are sent to our in-house pre-implantation genetics laboratory where they are tested to identify extra or missing chromosomes. All embryos are then frozen pending the results of the embryo screen. Any embryos in which there are no identified chromosome errors will be available for transfer to the uterus in the hope of establishing a pregnancy.
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Figure 2: Karyotype showing an extra copy of chromosome 21 (this type of embryo would not be transferred)
The Embyo Screening Process
See a fertility specialist
Undertake IVF cycle to create embryos
Embryo screening is performed following biopsy of a day 5/6 embryo
All embryos frozen pending results of embryo screening
Embryo with no detectable chromosomal errors is transferred to the woman’s uterus
Why do we perform Pre-implantation Genetic Screening? PGS is a way of screening embryos for randomly occurring chromosome errors to select only embryos with the correct number of chromosomes for transfer into the woman’s uterus. The aim of PGS is to increase the chance of pregnancy, decrease the chance of miscarriage and reduce the risk of an abnormal pregnancy.
How much does PGS cost? If your treatment involves PGS at Melbourne IVF, these services are charged in addition to your IVF cycle costs. Please contact our Community Liaison Administrators on 1800 111 483 for an indication of the additional cost.
More information If you would like further information about Pre-implantation Genetic Screening at Melbourne IVF, please contact our Community Liaison Administrators on 1800 111 483. Alternatively, you can speak with your Melbourne IVF fertility specialist for further information.
