Ovarian reserve is the quantity of primordial follicles present in the ovarian cortex that have the potential to mature into healthy oocytes. A high ovarian reserve typically results in a high chance of a successful pregnancy for couples. Fertility declines as women age because of changes in the ovarian reserve, and this decline is called ovarian aging. Diminished ovarian reserve (DOR) can impact fertility regardless of chronological age and can lead to embryonic aneuploidy, fertilization failure, and high pregnancy loss rates.