PGD stands for preimplantation genetic diagnosis, and is an advanced technique which allows us to prevent genetic diseases such as thalassemia, sickle cell anemia, hemophilia and Duchenne muscular dystrophy.
It's also useful in allowing us to select genetic normal embryos in older women. This is called
PGS ( preimplantation genetic screening) and uses CCS ( comprehensive chromosomal screening) for aneuploidy screening.
However, embryo biopsy is a complex technique which requires a lot of skill , and can be challenging to master.
This video shows Dr Sai, Chief Embryologist at Malpani Infertility Clinic, doing a trophectoderm biopsy for four Day 5 embryos ( blastocysts) . You can see that it's a very delicate procedure, and it's very easy for an unskilled embryologist to kill an embryo while doing PGD ! This is why you need to find an experienced and skilled IVF lab if you need PGD.
The biopsied cells are sent for genetic testing; and the normal embryos are transferred into the uterus, thus ensuring that they are disease-free.