Why does ageing affect egg quality?

The idea of a woman's egg quality is closely tied to both the age of the woman's egg and her ovarian reserve and has everything to do with the likelihood that an embryo will implant. We cannot assess egg quality by examining an egg, testing its sperm receptivity, or even observing how effectively the embryonic cells initially appear to be dividing. Ovarian reserve testing can be used to assess egg availability, but there is currently no test for egg quality; instead, the most accurate indicator of egg quality is the age of the female.