Fertility after 35: What happens to our eggs as we age?

Before she is born a baby girl has millions of eggs, but by the age of 35, about 95% have been lost and the remainder will be of poorer quality. But why?

Bourn Hall Clinic’s Medical Director, Dr Thomas Mathews explains:

“For the vast majority of women, the supply of eggs nestled away in the ovarian follicles when she is born will be enough to ensure she does not reach menopause before the age of 45.

“Each follicle provides the environment and hormones needed for an egg to mature. Each month there are about 15-20 follicles getting ready to release an egg, but only one will be ready at the right time.The other follicles will degenerate and die.

“This process is happening all the time but after the age of 35 the rate at which the follicles are lost begins to accelerate and their quality declines. Which means that the likelihood of one follicle being ready each month is less and this reduces the chance of conception.

“For some women however, premature ovarian failure (also called premature menopause) means that their ovaries lose their ability to ovulate before they should.”

Most women below 35, and in good health, will be able to conceive within two years of trying.  Being a healthy weight for your height, taking regular gentle exercise and a good diet will all maximise your chances of success.

However,  for women who have experienced a premature menopause or who have undergone cancer therapy, the chances of becoming pregnant with their own eggs is significantly reduced and for some not possible. For these women, using donated eggs may be their only chance of having a baby.

Egg donation: “the gift of a lifetime”

Dr Mathews continues: “Women younger than 35 who have completed their families could help a friend or family member to have a baby.  It is not a decision to make without considerable thought, but many women do not realise that they have the potential to give such a precious gift.”

Bourn Hall also has a successful egg sharing programme, which gives free IVF treatment to women prepared to donate half of their eggs to another woman during their own treatment cycle.

“Easter is a good time to highlight the need for egg donation and if anyone is interested we would warmly invite them to come and talk to us,” says Dr Mathews. “There is no obligation and after talking it through you might decide it is not for you and this is fine as women need to fully understand all the implications.  However, for those that do go ahead, it is truly the gift of a lifetime.”

Paula, an egg recipient who gave birth to twins Aiden and Ethan in March 2011, says:

“To anyone considering donating I would say, ‘be very sure that it is what you want to do’, it is not an easy decision. To give someone who craves a baby with her whole being the chance of being a mother is probably one of the most generous things you could ever do.

“I can still remember the pain when I was told I had no eggs and now I have these beautiful babies; I can’t begin to describe the joy.”