PGD is a sophisticated scientific technique that can be used to test embryos for either a specific, known genetic condition or chromosome abnormality.
Lynch syndrome is what’s known as a single gene disorder and, over the last 20 years, pre-implantation genetic diagnosis (PGD) has been applied to a great variety of single-gene disorders. In recent years, improvements in how embryos are screened and frozen mean that PGD has become a more realistic option for many more families.
Each embryo from a parent with a Lynch syndrome genetic mutation has a 50/50 chance of carrying that mutation. So, for a person with Lynch syndrome, the purpose of PGD would be to select an embryo that does not carry the gene mutation.
Firstly, the woman has to undertake an in-vitro fertilization (IVF) cycle: her unfertilized eggs are collected from the ovaries and these are fertilized with her partner’s sperm, in an effort to create several embryos. These embryos are then biopsied and genetically analysed. The ultimate aim is to transfer an embryo unaffected with Lynch syndrome back into the uterus.
To begin with, the ovaries are stimulated with follicle-stimulating hormone (FSH) injections, usually for 2 weeks, in an effort to stimulate multiple eggs to mature rather than just the one that occurs in a natural cycle.
The oocytes (eggs) are then usually collected vaginally – often under a light anaesthetic – and are fertilized with sperm that day.
The fertilized eggs, now embryos, are cultured in the laboratory for normally 5 days. On day 3, a process called assisted hatching (AH) is performed, where a laser is used to weaken the outer layer of the egg called the zona pellucida. This is to facilitate the embryo to hatch out of its zona (shell) on day 5.
The hatching cells can then be biopsied and genetically tested for the presence of the particular gene mutation causing Lynch syndrome. The testing normally takes several days so the embryos are usually frozen in liquid nitrogen after biopsy.
When the results become available, hopefully an unaffected embryo is available to be transferred back into the uterus (by frozen embryo transfer) often in a natural, drug-free cycle.
Like all fertility treatments, there are many things that can affect the success of PGD and these should all be considered before embarking on a course of treatment. These factors include: the woman’s age, her ovarian reserve (in other words, the capacity of the ovaries to produce egg cells that are healthy and capable of fertilization) her gynaecological health and the fertility of her partner.
All medical procedures have risks and, for IVF, these include pelvic infection or bleeding from the ovary at the time of oocyte retrieval which happens in about 1:4000 procedures.
Ovarian hyperstimulation syndrome (OHSS) occurs when a large number of eggs are retrieved (20+ eggs) which causes bloating, shortness of breathe and pelvic discomfort. OHSS affects about 1:100. Newer techniques are now available to minimize this risk, using a drug to mature the eggs before they are collected.
The biggest risk relates to the development of the embryos. Out of 10 eggs collected, on average about 6-7 would be expected to fertilize. Of those, probably only 1-3 would be suitable to be biopsied on day 5.
There is always the possibility that none of the embryos is suitable to be biopsied because development is not advanced enough and the embryos are not hatching.
It is also possible that all the embryos tested could come back affected by Lynch syndrome.
In 2010, there were almost 37,000 fresh IVF cycles performed in Australia.
At IVFAustralia, genetic testing of embryos makes up about 15% of the IVF treatment cycles. Currently, only a small percentage of these tests are to screen for a genetic mutation like Lynch syndrome.
While PGD is now more readily available than ever before, the complex procedure means that, unfortunately, IVF with PGD is not cheap. An IVF cycle typically costs around $9500 and, if the woman is privately insured, she is usually out of pocket by $4500. In addition, it costs $700 to test each embryo for Lynch syndrome.
Please don’t hesitate to contact me if you would like to discuss any aspect of IVF with PGD.
I am also happy to conduct Skype interviews to help people, particularly in rural areas or interstate.”
Dr Frank Quinn
176 Pacific Highway
02 9425 1600
Other useful resources can be found at:
About IVF clinics and costs:
Interpreting ‘success rates’
This is a consumer-controlled, independent, not-for-profit organisation committed to providing whole-of-life support for men and women who experience difficulties conceiving and to their families.
Access Australia has produced a helpful guide to IVF clinics and to assessing success rates:
And a list of accredited IVF centres in the country: