03 Apr Does PGD (PGT-M) boost IVF success rates?
PGD (now known as PGT-M) is a godsend for couples with known medical conditions that could be passed on to their offspring. And it’s getting better all the time. 1 in 100 babies inherit a serious parental disorder, but PGD/PGT-M is playing its part in tackling this. And in a new study of IVF embryonic DNA a way has been found to extract genetic material from a developing embryo without the need for a cell biopsy.
In standard PGD/PGT-M (pre-implantation genetic diagnosis) cells are taken from embryo cells created during IVF treatment. The aim is to find indicators for future inheritable diseases from either parent – usually ones the parents know about. Disease-free embryos are then transferred back into the uterus.
The current PGD/PGT-M method removes material from developing cells in a biopsy. This comes with slight risks attached. But a new approach takes fluid from the blastocoel, an area separated from the growing cells, which are left untouched. This cavity was originally thought to contain little or no genetic material. But, in around 90 per cent of cases, it does.
DNA in the blastocoel reveals information about the sex chromosomes. This could lead to the screening of sex-specific diseases. Crucially, the new technique can see if the normal number of chromosomes are present. Chromosomal abnormalities are the main stumbling block to successful IVF.
The number of conditions PGD/PGT-M screens for is large. Over 300 diseases are on the list, including cystic fibrosis and sickle cell disease. Treatment on the NHS has improved, but PGD is expensive when done privately. Embryo damage can happen. PGD doesn’t guarantee a healthy embryo will be transferred. If not enough eggs or embryos are created, it can’t be done. And finding out your embryos are faulty is stressful.
There are alternatives to PGD/PGT-M, but they are less cutting-edge. Amniocentesis and CVS are pre-natal tests carried out later in a natural or assisted pregnancy, often done when a problem is suspected. But PGD, carried out before a pregnancy, has many benefits and is lower risk.
Couples shouldn’t neglect other pre-conception tests for (mostly) non-genetic conditions that may reduce their chances. These include a hormone profile on female partners, an up-to-date semen analysis, a hysterosalpingogram and ultrasound testing. Karyotype testing, cheaper than PGD, may also negate the need for embryo testing.
And don’t rule out an evaluation of your diet. Or if you smoke or suffer from stress. Any one of these assessments could pave the way for an improved pregnancy outcome. Not all genetic conditions are passed on anyway. Pre-implantation genetic diagnosis is an increasingly appealing option for couples with a serious genetic condition on one or both sides. But it’s also one piece in the jigsaw.