The rate of attrition of a woman’s lifetime stock of oocytes is inexorable. Despite controversial research suggesting that under certain circumstances the ovary might repopulate itself by differentiation of stem cells into follicles and oocytes, the picture in clinical practice now, and in the foreseeable future, is one of managing the decline in fertility and increase in rates of miscarriage and chromosomal abnormalities in offspring that result from reproductive ageing in the female.
‘Unexplained infertility’ is a rare diagnosis for a couple where the woman is in her 20s, but becomes the most common cause of infertility in women over 35 years of age. This increase follows from the decline in oocyte ‘quality’ seen as the consequence of ageing in women. Quality in this context refers to a complex series of age-related changes in nuclear and cytoplasmic competence, affecting such fundamental processes as spindle formation and chromosome segregation, mitochondrial function and the integrity of the cytoskeleton. A poor-quality oocyte is less likely to fertilise and, if fertilised, will produce an embryo which is generally slow to divide and unlikely to implant.
This paper assesses current methods for measuring ovarian reserve, discusses the complications of reproductive ageing and their consequences and describes available strategies to ameliorate their impact on fertility, and also touches on reproductive ageing in the male.