What is Preimplantation Genetic Diagnosis (PGD)?
Did you know that up to a third of embryos created do not survive the first 3 months on pregnancy? Some embryo’s also do not achieve implantation due to a genetic disorder or abnormal chromosomes.
To increase the chance of pregnancy a Preimplantation Genetic Diagnosis (PGD) can help to discover if there is something irregular with the structure of the embryo. When an embryo has abnormal chromosomes, there is a higher risk of miscarriage, or the result of a child being born with mental or physical disabilities.
What is Preimplantation Genetic Diagnosis Screening?
Screening is required for a Preimplantation Genetic Diagnosis (PGD). The testing is a sophisticated scientific technique which is used to test for genetic disorders. Due to examining the DNA directly, the embryos can be tested for specific known conditions or a chromosome abnormality.
This process maximises the chance of a healthy baby during IVF [link to IVF page] as only embryo’s containing normal chromosomes or unaffected by a genetic disorder are selected for transfer.
Why have a PGD screening?
Reducing the risk of miscarrying
When an embryo has a chromosome abnormality, it decreases the chance of implantation to the lining of the uterus and can result in a miscarriage. 50% of miscarriages are due to the embryo containing abnormal chromosomes. By screening the embryo first we can reduce this number as only ones containing normal chromosomes are transferred.
Recent studies have shown that the number of miscarriages has gone down from 23% to 9% after PGD screening has occurred.
Reducing the risk of the child being born with abnormal chromosomes
Even though genetic testing is not 100% accurate, PGD screening reduces the chance of the child being born with abnormal chromosomes.
PGD screening can also test for a wide range of single gene disorders, such as Cystic fibrosis, Huntington’s disease, Thalassemia and Duchenne muscular dystrophy
Improving the success rates of IVF treatment
Embryos with abnormal chromosomes are less likely to survive and have a lower implantation rate.
PGD screening allows for selection and transfer of embryo’s containing normal chromosomes which generally increase the chance of the embryo implanting and surviving. PGD screening also reduces the risk of IVF failing, leading to a reduction in the amount of cycles needed.
Who is PGD screening suitable for?
You may want to consider PGD screening if:
- One or both partners have the risk of passing a genetic disorder onto future children (from family history)
- Either partner has a chromosome rearrangement that can lead to genetically abnormal eggs or sperm
- A previous pregnancy has been affected by abnormal chromosomes
- Have experienced several miscarriages without explanation
- The woman is of a mature age (38 years of age)
- Repeated IVF failure
What is the PGD screening procedure?
For PGD screening, the chromosomes are tested by removing a few cells from each embryo whilst developing in the laboratory. This allows for analysis to take place.
What are the risks of PGD screening?
Although there are many benefits to PGD screening, the procedure could carry some risks:
- No test is able to retrieve a 100% diagnosis of abnormal chromosomes, meaning results from PGD screening are extremely accurate but not 100%
- There is a 1% chance of embryo damage during the biopsy. If the embryo is damaged, then it will not be able to be transferred.
Preimplantation Genetic Screening & Diagnosis Brisbane
For full details on the PGD screening procedure contact Dr Sharon Li today!