egg donors and ageThe world's first baby conceived through egg donation by Monash IVF was born in 1983. Since then, hundreds of donor egg programs have been established throughout the world.
Unfortunately there is difficulty in obtaining egg donors.
Egg donors may be:
- Altruistic - donating to the clinic for any couple and allocated by the clinic
- Known to the recipient couple
- Unknown to the recipient couple
Selecting donors
 The ideal egg donor should be young (<35), in overall good health and not have or be a carrier of any known genetic disease.
These donors should have normal fertility and therefore overcome some of the reasons that egg donation is required. Older donors may be considered at the discretion of the clinician and the couple, provided that the effect of age on the fertility of the donor and the pregnancy is understood.
As women become older, the chance of becoming pregnant is lower, the chance of having a miscarriage is higher and there is an increased risk of chromosomal abnormalities in the baby. In the general population, the chance of becoming pregnant after the age of 40 is estimated to be only 5% per cycle, compared to about 20% per cycle in the under 40 age groups. One-third of couples where the woman is over 35 may have fertility problems. Treatments such as IVF cannot reverse the effects of age on fertility.
Reasons for decline in fertility
There is an increased incidence of gynaecological problems as women age. Endometriosis, fibroids, and pelvic infections all may reduce fertility, however the aging of eggs is thought to be the major cause of reduced fertility. Girls are born with about 400,000 eggs in their ovaries.
The eggs are matured and ovulated during each menstrual cycle. For every egg that is released, many more degenerate and are reabsorbed into the body. Eventually the ovary does not respond to the hormones that mature and release eggs, and the woman experiences menopause. Because eggs are present in the ovaries from birth, they age as the woman grows older, reducing their quality, so at 12 - 13 years old when menstruation starts the eggs released are 12 - 13 years old and at 40 years the eggs are 40 years old.
This is in contrast to male reproduction where sperm are constantly manufactured and replaced. The ageing of eggs reduces their ability to be fertilised and to divide properly, leading to chromosomal abnormalities such as Downs Syndrome and a higher risk of miscarriage. The risk of Downs Syndrome at 36 is 1 in 300 and at 40 it is 1 in 100 pregnancies.
Success rates
The pregnancy rate of donor egg treatment by Monash IVF approximates 25% per cycle and is directly related to the number and quality of donated eggs.
Older women who receive eggs from a younger donor have a much higher chance of conceiving, confirming that the age of eggs is crucial in achieving a pregnancy.
In IVF, age has a number of effects on the success of the treatment. The number of eggs collected is lower in older donors and the quality of the embryos also generally decreases. This may have been the reason to suggest egg donation initially.
Higher doses of hormones are usually required in older women and there is also a higher risk of not having an egg collection due to poor or no response to the stimulating drugs. Unfortunately there is no way to reverse these effects.
If all these factors are understood and there is still a request for considering using a donor older than 35 years, please discuss this with your clinician.
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