Every year hundreds of thousands of babies are born with genetic diseases, with some studies stating that about 5% of babies are prone to inherit one of more than 6,000 hereditary diseases passed down from one or both parents. Common genetic disorders include Down syndrome, sickle-cell anaemia, spina bifida, muscular dystrophy, and cystic fibrosis, all of which can cause significant discomfort and illness during childhood and later in life.
With so much suffering being caused by hereditary disorders, one of the most pertinent challenges for the medical community has been finding a way to prevent these “bad genes” from being passed on to future generations. One approach in particular, pre-implantation genetic diagnosis (PGD), has been highly effective and is even allowing couples carrying hereditary diseases to reproduce without passing their genetic disorders on to their offspring.
In the following paragraphs we’ll discuss how and why PGD is becoming one of the most useful and popular assisted reproduction techniques available.
How Does Pre-Implantation Genetic Diagnosis Work?
Pre-implantation genetic diagnosis is used in conjunction with in vitro fertilization (IVF) and intracytoplasmic sperm injection (ICSI). The doctor’s perform IVF as usual, except after the embryos have been developed they are then genetically assessed and tested for abnormalities that could result in hereditary disorders. An embryology expert can remove the problematic cell from the embryo before it is injected into the woman’s uterus, thereby removing the cause of the genetic disorder.
When is PGD Recommended?
A doctor may recommend PGD to couples preparing for IVF if one or both parents is a carrier of a genetic disorder or if they have family members who are, or if the mother is of an older maternal age or has had multiple miscarriages. PGD is not typically recommended for couples who do not have any history of genetic disorders, but it is still possible to use the diagnostic part of this technique as a precautionary measure, just to be on the safe side. Many clinics, like the IVI assisted reproduction clinic for example, will offer to provide a full refund if the couple is unable to conceive a healthy baby within three IVF cycles.
What are the Steps Involved in PGD?
PGD is performed as part of the IVF process, after the doctor has removed the eggs, injected the sperm, and begun to develop embryos. After three days of being in a culture dish, the embryo is biopsied – one to two cells are removed from the embryo, which at this point consists of about 8 cells. The extracted cells are then tested for the presence of chromosomal abnormalities, and within 2 days the lab analyses the results and chooses an embryo that is not affected by a genetic disorder to be transferred into the woman’s uterus. Typically the couple will know the results of the diagnosis on the same day of the embryo transfer.
Not a Replacement for Prenatal Testing
Now that we’ve provided a basic summary on what PGD is and how it works, we should note that this procedure is not a substitute for prenatal testing, which is still considered to be the standard of care by the medical community. Be sure to talk to your doctor about the differences between PGD and prenatal testing to further address any curiosities you might have in this regard.