Women of advanced maternal age (≥ 37) are at a higher risk of producing aneuploid embryos, resulting in implantation failure, a higher risk of miscarriage or the birth of a child with a chromosome abnormality (e.g. Down syndrome).

This is due to the fact that all of the woman's eggs are present at birth. Over time, the chromosomes within the egg are less likely to divide properly, resulting in cells with too many or too few chromosomes.

Aneuploidy is also believed to be a major reason for the decrease of fertility with age. Several studies have determined that approximately 70% of embryos from women of advanced maternal age may be aneuploid.

For women aged 37 years and older undergoing IVF, PGD for aneuploidy significantly improves pregnancy rates, reduces miscarriage rates, and decreases the chance of a chromosomally abnormal pregnancy if six or more embryos of good quality are available for analysis.