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Guide for Older Women

Why is age important?

Age is an important independent factor affecting female fertility. Women are waiting longer to begin a family. Age related decline in fertility may take place at a quicker pace than what most women expect. This is due to age related decline in the number and quality of eggs in the ovaries. Decline in natural fertility accelerates after the age of 35 years and this decline is not completely offset by assisted conception treatments. The chance of a live birth following IVF treatment with fresh embryo transfer varies with age. This is 32% for women below 35 years of age and declines to 13.6% for a woman who is 40 years of age (National averages, HFEA).


What is ovarian reserve?

Women are born with a fixed number of egg containing follicles in the ovaries. At birth this may number around 1 million. By the onset of puberty this number would have dropped to around 300,000. Only about 300 would be ovulated during the reproductive years and the rest of the egg containing follicles are lost by a process called atresia. This process of atresia is gradual and is not offset by pregnancy or being on the contraceptive pill. This rate of loss of egg containing follicles may vary from woman to woman. Smoking accelerates this loss of egg containing follicles (ASRM, 2012). This decline in egg quantity is called 'loss of ovarian reserve'. Blood tests for hormones such as follicle stimulating hormone (FSH), Anti-mullerian hormone (AMH) and an ultrasound for checking the antral follicle count (AFC) give an assessment of ovarian reserve.


Egg quality and advancing age

Advancing age also has an impact on egg quality. An important reason for decline in egg quality is due to increased frequency of genetic abnormalities in the egg with increasing age. This results in lower success with assisted conception and an increase in miscarriage.

Women who are over 35 years of age should seek advice sooner from their GP if they are finding it difficult to achieve a pregnancy.