The natural ageing process described in our “Egg and Ovulation Problems” page can be charted to show how average fertility starts declining at 35 and ends altogether at 51. However, approximately 11% of women will reach menopause early. For reasons still unknown, their rate of fertility decline will follow the same timeline as normal but with an earlier start date. Therefore their fertility will start declining well before the age of 35. For these women it is important to start their families earlier or else they will be forced to find another solution, such as adopting or receiving donated eggs from a donor.