Preimplantation Genetic Screening & Diagnosis
Assisted reproductive technology (ART) is a field of medicine for the treatment of infertility. ART assists in the fertilization of the sperm and egg (outside a woman’s body, in a lab), either through in vitro fertilization (IVF) or intra-cytoplasmic sperm injection (ICSI). Preimplantation genetic screening (PGS) is a diagnostic tool used to examine embryos formed through these methods, for chromosomal abnormalities, which is the chief cause of miscarriage and embryo implantation failure in the womb. The process is also called aneuploidy screening as it identifies aneuploidy abnormalities, which refers to the presence of an abnormal number of chromosomes.
PGS is recommended for women over 35 years of age with repeated implantation failures, recurrent pregnancy losses, family history of chromosomal problems and partners with male factor infertility.
Your doctor first performs normal IVF procedures, which involves the collection of mature eggs from the ovaries and fertilization with sperm in the lab. The resulting embryos are cultured in the laboratory for two to three days or five to six days, until the embryo has several actively dividing cells. A few cells are removed at this stage and tested for chromosomal abnormalities. The healthy embryos are then transferred into the womb for development, while those with abnormal number of chromosomes are destroyed.
As with any procedure, PGS may involve certain risks and complications such as the probability of having no embryos left for transfer after the screening or the damage of some during the cell removal process. It is important to remember that PGS screening does not guarantee against miscarriages.