In order to be able to perform Preimplantation Genetic Diagnosis - PGD a sample or biopsy of the embryo that contains genetic information must be obtained. The polar bodies contain genetic information that can be used for preimplantation genetic diagnosis - PGD. As indicated in the section on IVF, the first polar body is produced from the division of the egg and can be removed and tested for its chromosome complement or to identify whether it contains the abnormal gene of concern. Upon penetration of the egg by the sperm (fertilization), but prior to the joining of the sperm’s genetic material with the egg’s genetic material, the second polar body is produced. The polar bodies have no known function except to assist in cell division. They are simply “by-products” of the egg’s division. Once implantation occurs, the polar bodies disintegrate and are not part of the developing fetus.

By testing the first and second polar bodies, the genetic make-up of the egg, and maternal genetic contribution in the resultant embryo, can be determined. Removal and genetic analysis of the polar bodies occurs on the first and second day after aspiration.

In some instances, it is necessary to confirm a diagnosis made on polar body analysis by performing blastomere biopsy. It is also possible that one or more polar bodies fail to provide a conclusive result. In these situations, it may be possible to perform blastomere biopsy (embryo biopsy) for further genetic analysis.

Learn more about blastomere biopsy

Learn more about trophoblast biopsy