Pre-Implantation Genetic Diagnosis (PGD)
If you or your partner carry the risk of inherited conditions, such as birth defects or genetic disorders, you may decide to undertake some genetic testing as part of your fertility treatment program.
Who should consider PGD?
If you are concerned about any of the following issues, PGD may give you peace of mind – and help us select an unaffected embryo for transfer.
- Risk of your baby inheriting a known genetic condition
- Known family history of chromosome rearrangement in your or your partner
Some of the single gene disorders we can test for include Huntington’s Disease, Cystic fibroisis, Thalassaemia and Fragile X. Please discuss any genetic concerns or risks with your fertility specialist to find out more about this procedure.
What is Pre-implantation Genetic Diagnosis?
Pre-implantaton genetic diagnosis or PGD is a highly sophisticated technique that tests embryos for a specific genetic or chromosomal abnormality. It allows us to select embryos that are not affected with the condition being tested for, prior to implantation and pregnancy. PGD is offered in conjunction with an IVF cycle.
For PGD for chromosomal anomalies such as Robertsonian translocaton and, genetic mutations such as thalassaemia, a biopsy of the blastocyst is usually performed where a few cells (3-5 cells) are taken from the trophectoderm. This approach significantly reduces the chance of a misdiagnosis as compared with one or two cells taken from an 8-cell embryo. The outcome of pregnancy after the transfer of a biopsied normal blastocyst is better than the transfer of a biopsied normal 8-cell embryo.
Preimplantation genetic diagnosis (PGD) is being used increasingly at the fertility Institutes to dramatically improve the chance of a successful IVF pregnancy in couples where prior IVF failures have remained unexplained. It has been estimated that over half of all IVF failures are not able to be explained by an apparent problem with embryo “quality”. For many couples however, this statistic is quite misleading. AngelLife IVF embryologists looks very closely at the appearance of embryos under the microscope as they attempt to determine a “good” or “high quality” embryo from those of lesser quality. Generally, embryos are given “good” marks when they demonstrate an appropriate number of cell divisions at a given time in their growth cycle, when the individual cells of the embryo appear to have a uniform size and when there is an absence of cellular “fragments” that may or may not represent problems in the growth progress of the embryo.
Successful Use of PGD for Recurrent IVF Failure
Most couples presenting to us for consideration of PGD have one of the following conditions:
- Prior unexplained IVF failure
- Recurrent miscarriages
- Maternal age over 38
- Conception of a chromosomally abnormal child or fetus
- Polycystic ovary syndrome
- History of ovarian hyperstimulation syndrome
- Heritable medical condition in either the patient or in a prior child (such as hemophilia)
- Two or more children of the same gender (gender selection for family balancing)
- Multiple birth with desire to transfer just one embryo or a need for donor oocytes due to Turner’s syndrome
- Premature ovarian failure or premature menopause
Using PGD to select the best embryos is clearly superior to traditional methods of selection. Miscarriage rates following PGD are far less than with standard IVF. Currently more than half of couples with two or more normal embryos and maternal age under 41 will take home a baby on a first IVF-PGD attempt in our program. And these are in couples who have failed multiple prior IVF attempts elsewhere!