There are many possible causes for miscarriage. About 50% of first trimester miscarriages are due to a chromosome abnormality. This may be related to a patient’s age or a rearrangement in a parent’s chromosomes that predisposes conceptions with chromosome abnormalities. PGT can be performed for either of these possibilities. For patients over 35, the greatest risk may be for aneuploidy, a pregnancy with the wrong number of chromosomes, such as Down syndrome. PGT for aneuploidy screening offers these women a greater chance of a successful and healthy pregnancy. If a parent has a balanced structural chromosome rearrangement, such as a translocation, a different type of PGT is available.