PGD Procedure

PGD can only be performed on embryos in vitro (in a laboratory). That means this test is always performed in conjunction with an in vitro fertilization cycle.

In Vitro Fertilization (very brief summary)
Medication is given to stimulate the production of multiple eggs.

• Egg retrieval is performed using an ultrasound guided needle.
• Eggs are then mixed with the partner’s sperm in the IVF Laboratory and placed in the incubator for fertilization and embryo growth to the 4 - 12 cell stage.
• At this point, one or two cells will be biopsied from the embryo(s) and PGD will be performed.
• Normal embryos are transferred to the mother’s uterus on day 4-5 following egg retrieval.

Embryo Biopsy
To enable screening of a human embryo before transfer to the uterus, it is possible to remove one or two cells from the early multi-celled embryo so that the genetic material in these cells can be analyzed. It must be noted that in routine genetic analysis there are usually hundreds of cells available for processing; however, with embryo biopsy only one or two cells are commonly available, and they must contain a nucleus with chromosomes present to determine the genetic status of the rest of the embryo. The biopsy method is relatively straightforward, but this does not mean that it is an easy procedure to undertake. The embryos are typically biopsied at the pre-implantation stage on day three of development. At this point, the embryo will be composed of between four and 12 cells that are still distinct from each other. By the third day of development, or at the latest on day four, the embryo begins to compact, a process whereby the individual cells lose their clear outline and they seem to fuse together with the other cells to form the morula stage embryo. On the third day, however, single cells can be individually removed without disrupting the adjacent cells in the embryo.

Next>