Published online by Cambridge University Press: 15 September 2022
The loss of oocytes and reduced oocyte quality contribute to age-associated ovarian decline and decreased fertility, which is at odds with the social trend toward delayed family building. Females are born with a finite cohort of germ cells, arrested from mid-gestation, and they progressively lose them throughout their reproductive lifespan, reaching a state of near depletion at menopause. Declining oocyte number, however, is not the sole culprit for age-related infertility. Oocyte competence, the ability to fertilize, develop, implant, and produce a live offspring, deteriorates more or less in concert with declining ovarian reserve. The uterus likely also plays a role, further hindering reproduction later in life, though additional studies are needed.