Preimplantation Genetic Testing for Aneuploidy (PGT-A) is a screening procedure performed on embryos created through in vitro fertilization (IVF). It analyzes the number of chromosomes present in cells biopsied from the developing embryo. The primary goal is to identify embryos with a normal chromosome count (euploid) for transfer to the uterus, thereby increasing the likelihood of successful implantation and a healthy pregnancy. Chromosomal abnormalities, such as trisomies (an extra chromosome), are a common cause of miscarriage and can lead to genetic disorders in offspring.
The significance of chromosomal screening lies in its potential to improve IVF outcomes, particularly for women of advanced maternal age, who have a higher risk of producing eggs with chromosomal errors. By selecting embryos with a balanced chromosomal complement, the chances of a successful pregnancy and live birth are increased. Historically, detecting chromosomal abnormalities relied primarily on prenatal diagnostic tests like amniocentesis or chorionic villus sampling (CVS) performed during pregnancy. PGT-A offers the opportunity to screen for these abnormalities prior to implantation, potentially reducing the need for later invasive testing and termination of affected pregnancies. The ethical considerations surrounding embryo selection are an important part of this.
