Female fertility rates are inherently linked to a woman's age, which is in turn related to ovarian function. Reproductive potential declines gradually until 37-38 years of age, from when the rate of decline hastens. Approximately 1% of women suffer from premature ovarian ageing, and many may not have completed their families. This paper reviews the physiology and fertility consequences of ovarian ageing, premature ovarian failure, measures of ovarian reserve and methods of fertility preservation.