Preimplantation Genetic Diagnosis Testing at a Fertility Clinic
- Posted on: Jun 7 2013
Fertility specialists performing in vitro fertilization (IVF) are able to use an advanced screening and diagnostic testing to assess if an embryo carries certain genetic abnormalities before pregnancy begins. This procedure is known as preimplantation diagnosis or PGD.
Preimplantation diagnosis and screening is used for a variety of reason but in general will detect genes that may contribute to abnormalities and disease in a baby. Chromosomal abnormalities or single gene defects (ie-testing for diseases such as sickle cell disease , cystic fibrosis, SMA) can be detected through preimplantation screening and is designed to help women who are at risk for genetic errors. The embryos with the normal number of chromosomes or absence of a particular disease can be selected for transfer, improving the likelihood and success rate of a healthy baby.
Why is PGD Necessary?
The procedure is utilized to decrease the risk that a couple will give birth to a child with a genetic disorder. In order to undergo PGD, In Vitro Fertilization (IVF) must be performed and requires that a couple conceive in vitro so that the embryos may be screened ahead of time for any genetic abnormalities and defects.
Those who may benefit from PGD include:
- Women over the age of 35
- Known or possible carriers of sex-linked genetic disorders
- Couples with chromosomal disorders such as a balanced translocation
- Those with single gene defects such as sickle cell disease, cystic fibrosis etc
- Women who have experienced recurring pregnancy loss and the losses may be due to genetic problems
How is PGD Performed?
PGD begins with carrying out a normal Denver IVF procedure. Ovary stimulation with medicine, retrieval of eggs, and fertilization conducted in the laboratory are conducted. After three days the embryo divides into eight cells, on day 5 the embryo can develop to the blastocyst stage. Testing can be performed on day 3 embryos that have 6 or more cells or on Blastocyst stage embryos on day 5 or 6 of development. There are risks and benefits to testing at each stage of development which can be discussed with your Denver Infertility specialist.
The first step in PGD involves the removal of cells from the embryo. DNA is then retrieved from the cell and copied. This process is known as PCR or polymerase chain reaction. The DNA is analyzed with a microarray and all 24 chromosomes can be tested. After the genetic problems have been evaluated, implantation may be carried out through embryo transfer.
Benefits of PGD
There are a variety of benefits that this procedure offers by detecting genetic birth defects prior to pregnancy/ implantation. When it is performed prior to implantation, the need for amniocentesis is greatly reduced. Birth defects may be identified early on and in many cases avoided through the conduction of this procedure before implantation.
If you are concerned about a chromosomal or genetic disorder that could be passed to your child, it is important to discuss PGD options with your Colorado fertility doctor. Screening can take place prior to pregnancy and greatly reduces the risk of chromosomal defects and genetic abnormalities in a child.
Posted in: Genetics