What is a Pre-Implantation Genetic Diagnosis(PGD) Test?

Many times, when presented with the options, intending parents ask us ‘what is PGD?‘

PGD stands for Pre-Implantation Genetic Diagnosis, sometimes referred to as embryo screening, and this reproductive technology is used in the in-vitro fertilization (IVF) cycle to diagnose genetic diseases in early embryos prior to implantation into the surrogate mother.

What is the Purpose of Pre-implantation Genetic Testing?

In simple terms, preimplantation genetic testing is a form of gene-level diagnosis, which is usually carried out on embryos prior to embryo transfer for the purposes of surrogacy. The test is conducted to check for genetic abnormalities. The embryos which are declared to be genetically normal will be used for the embryo transfer process.

PGD helps reduce the risk of miscarriages, and any complications related to pregnancy failure, prevents undesired genetic traits and thereby improves the chances of a successful pregnancy.

Who should undergo PGD?

As a general rule of thumb, almost anyone who wants to pursue surrogacy must consider a preimplantation genetic diagnosis. But the test is doubly important if:

  • The Intended Parents have ended previous pregnancies because of a serious genetic condition
  • The Intended Parents already have a child with a serious genetic condition
  • The Intended Parents have a family history of a serious genetic condition
  • One or both of the Intended Parents have a family history of chromosome problems

What is the Pre-Implantation Genetic Diagnosis(PGD) Procedure?

Step 1. The patient undergoes the normal in-vitro fertilization (IVF) treatment to collect and fertilize their eggs.

Step 2. The collected embryo is grown in a laboratory for two to three days until the cells have divided and the embryo consists of around 4-12 cells. This process can take anywhere from three to five days.

Step 3. A trained embryologist removes one or two of the cells from the embryo for testing purposes.

Step 4. The cells are tested to see if the embryo from which they were removed contains the gene that causes the genetic condition in the family. (these conditions have to be mentioned by the patient before testing.)

Step 5. The embryo unaffected by the condition is transferred to the womb 4-5 days following the egg retrieval, to allow it to develop into a pregnancy.

Step 6. Any remaining unaffected embryos can be frozen for later use. Those embryos that are affected by the condition are allowed to perish or, with the patient’s consent, used for research.

Why a PGD is a must for all Intending Parents?

The most important reason to undertake a preimplantation genetic diagnosis test is that it can detect over 100 different genetic conditions in an embryo. Simply undergoing this test will help increase the chances of ensuring that your baby is healthy, free from diseases, and has a complication-free birth.

Since the procedure happens before implantation, it allows Intending Parents to decide if they wish to continue with the surrogate’s pregnancy. It’s important to keep in mind, however, that it doesn’t completely eliminate the risk of conceiving a child with a genetic disorder. It is also important to note that preimplantation genetic diagnosis does not replace the recommendation for prenatal testing.

Can PGD have an adverse effect on the pregnancy and child’s development?

It is an unfortunate misconception that performing PGD and manipulating the embryo for medical reasons is likely to lessen the chances of pregnancy or introduce some complications to the process. The preimplantation genetic testing procedure is done in a manner that has no effect on the chances of pregnancy or the health of the embryo. Keep in mind however that pregnancy rates are highly dependent upon the medical procedure, the skills of the embryologist and your personal factors.

In fact, recent research suggests that pregnancy success rates actually increase through the use of PGD because only those embryos that have been shown to be in good health are transferred back to the mother.

Also, since genetic abnormalities are among the most common reason for a miscarriage, the transferal of embryos that are absent of any abnormalities decreases the risk of another miscarriage. PGD can help reduce the chances of genetic disorders like diabetes and down syndrome.

If you’re interested in learning more about PGD testing, talk to our Surrogacy Experts by filling up the contact form.