Preimplantation Genetic Diagnosis (PGD) involves screening single cells from embryos for genetic diseases and chromosomal disorders. This testing is performed with in-vitro fertilization (IVF) and occurs prior to embryo transfer, before a pregnancy is established. PGD offers at-risk couples the opportunity to select embryos for transfer based on their genetic and chromosomal status.
The goal of PGD is to identify abnormal embryos so they will not be transferred, leaving unaffected embryos to be selected for transfer that are more likely to make healthy, disease-free babies.
PGD can identify the presence of chromosomal translocations (rearrangements of parts of chromosomes) and single-gene disorders (genetic diseases that are the result of a single mutated gene).
PGD technology is also used to determine the gender of the embryo (Gender selection) prior to the transfer into the uterus.
Preimplantation Genetic Screening (PGS) applies the technology from PGD to improve the chances for a successful pregnancy. Embryos are screened for aneuploidy (missing or additional numbers of chromosomes), which is a leading cause of miscarriage and implantation failure.
The goal of PGS is to identify chromosomally abnormal embryos to prevent their transfer and save the maximum chances of achieving a successful pregnancy.