PGD with IVF
If you are undergoing fertility treatment with in vitro fertilization (IVF), you can choose to have preimplantation genetic diagnosis (PGD). Your fertility doctor at HRC may recommend PGD, particularly if you are at risk of passing on a genetic disorder or if you have suffered from recurrent miscarriage. This laboratory technique screens for single-gene defects that may cause genetic disorders when one or both genetic parents carry a gene mutation or a balanced chromosomal rearrangement. PGD is performed to determine whether that specific mutation or an unbalanced chromosome has been transmitted to the egg or embryo.
With PGD, the egg is fertilized in a laboratory via IVF using the egg and sperm from the couple or from an egg donor or sperm donor. Then a single cell is taken from a Day 3 embryo, or six to eight cells are taken from a Day 5 or 6 blastocyst. The cells are removed and the chromosomes examined for genetic abnormalities by geneticists and specialists using one of several techniques. At HRC Fertility, the PGD methods used to examine the chromosomes include fluorescent in situ hybridization (FISH) and/or the polymerase chain reaction (PCR). FISH involves labeling the chromosomes with a fluorescent tag allowing them to be examined by the embryologist, while PCR enables making multiple copies of the DNA segments.
The embryonic cells continue to divide without the removed cell or cells. Studies have shown that any risk of damage to the embryo is small, and there is no increased risk of birth defects.
If a problem is found with an embryo, the couple can decide to transfer only the "good" embryos. PGD can screen out more than 50 genetic diseases, such as cystic fibrosis, Down syndrome, Tay-Sachs disease, spinal muscular atrophy and hemophilia A and B.
PGD may also be used to help couples select the gender of their child whether it is for family balancing or to try to prevent the transmission of a sex-linked genetic disease (a disease carried on the sex chromosome).
HRC Fertility was one of the first clinics to perform PGD using a laser, and one of very few using a laser to date. The laser affords the embryos less exposure to handling and general outside conditions while undergoing PGD.