ABSTRACT
Age-related decline of fertility The age -related decline of fertility in women is a phenomenon that has been established beyond any doubt in both contemporary populations4 and historic natural fertility populations (i.e. populations that did not have access to or were denied contraceptive measures because of religious reasons). These studies showed that a similar pattern of age -related fertility decline exists worldwide, which starts from the age of 25 and accelerates after the age of 30 years (Figure 2)5,6. The results of in vitro fertilization (IVF) treatments also reflect the effect of female reproductive aging: increasing age is significantly associated with reduced implantation, pregnancy and live-birth rates 7,8. In natural fertility populations, the mean age at last childbirth is 41 years. This age is considered to be a proxy for the end of the effective fertile period, i.e. the period in life during which a woman is able to achieve a pregnancy that leads to a live birth. At this time the majority of women still have a regular menstrual pattern. Cycles become irregular only at a mean age of 45 years5,9. The menopause, the cessation of menstrual bleeding in a woman’s life, occurs at a mean age of 51 years.
