PGD: Pre-Implantation Genetic Diagnosis
Pre-implantation genetic diagnosis, also referred to as PGD, is used to identify the gender of an embryo as well as to screen for a variety of known disorders. PGD involves essentially the same steps as in routine IVF: ovarian stimulation to produce many eggs, which is followed by insemination of the eggs with sperm to achieve fertilization. On Day Three of the process (approximately 72 hours after egg retrieval), when the embryos are at the four-to-eight-cell stage and beyond, one cell is removed from each embryo under the microscope. This is called embryo biopsy.
Then, using a specialized technique called fluorescent in situ hybridization or “FISH,” the female (XX) or male (XY) embryos can be identified with certainty and only embryos of the desired sex transferred. Following transfer, management of the patient is essentially the same as in routine IVF.
Further information on this advanced procedure is available here including a short video of an embryo biopsy performed under the microscope in the laboratory of New York Fertility Institute.
Assessing Embryo Health
Advanced medical technology gives new options for reproductive health and can improve outcomes for women looking to conceive. Besides the flexibility afforded through gender selection, the same advanced laboratory techniques can help detect chromosomal abnormalities in embryos before implantation so that only the healthiest are selected, thereby reducing risk of miscarriage and improving peace of mind of the mother-to-be.
On Day 3 or 4 of the IVF process (see How IVF Works for details), a biopsy is performed whereby a cell is extracted from the embryo. The video below shows the cell removal as done under a microscope in the New York Fertility Institute laboratory.
Analysis of the Cell Using FISH
This single cell is fixed on a slide and analyzed by the technique of fluorescent in situ hybridization or “FISH,” which allows direct inspection of specific chromosomes to determine the number or absence of the chromosomes. FISH also is used to assess the genetic health of the embryo and detect chromosomal abnormalities. With modern science, a high percentage of abnormalities which typically cause miscarriage have been identified and embryos containing these irregularities can be screened out, thus improving the potential outcomes by selecting only the healthiest embryos for implantation.
The highly-trained medical professionals at New York Fertility Institute have extensive experience with these specialized procedures which can help improve your chances for a successful pregnancy.