A woman is most fertile in her 20s and 30s, but not all women are ready to have a baby at that stage in their lives.
To date, about 5,000 babies in the world have been born following egg freezing (oocyte preservation). And more and more women are considering it for social reasons when they’re in their late 20s and 30s with the hope to have a baby in future.
But why freeze eggs and how effective is IVF for older women? How does the egg freezing process work?
Why freeze eggs?If a woman wants a family in future but is unable to start one in her most fertile years, freezing her eggs when she is younger may allow her the possibility of having a biological child in future. The eggs are frozen unfertilised and can be thawed at a later date and fertilised with sperm, creating embryos that can be implanted in her uterus.
As a woman ages, the quality of her eggs declines; and even more so in her 40s. This may mean that some women are unable to get pregnant as they get older. Or, if they do get pregnant, they are at an increased risk of miscarriage and having a baby with chromosomal defects like Down syndrome. Whilst the embryos can be tested for abnormalities before implanting, eggs frozen when a woman is under 35 usually have a better chance of pregnancy and lower chance of abnormalities. Therefore, women who are interested in freezing their embryos should consider speaking to their doctor about egg harvesting as quickly as possible.
What is involved in egg freezing?The egg harvesting process takes place over the course of a couple of weeks.
Egg freezing involves hormonal stimulation of the woman’s ovaries for 10-14 days, which stimulates a group of eggs to mature in the ovaries. When the eggs are mature they are extracted from the ovaries by a surgical procedure, which is performed in a day hospital under general anaesthetic. This procedure, which takes approximately 15 minutes, is under ultrasound guidance. An average of 10-12 eggs are usually collected from each round of egg collection. Eggs are then frozen (cryopreserved) with a special technique called vitrification.
How effective is egg freezing?
Egg freezing success rates depend on a number of factors:
- The age of the woman when her eggs are frozen: younger women (under 35) tend to have better pregnancy rates.
- The number of eggs in her ovary (egg reserve): this is tested using a procedure called Antral Follicle Count (AFC) by ovarian ultrasound and a blood test called AMH.
- The response of the ovaries to hormonal stimulation has a strong impact on egg freezing success rates.
- The quality of the eggs: this is not measurable at the time of egg collection but is an important factor for embryo quality and pregnancy potential of the egg in future.
Currently, we would usually expect that:
- On average, 10-12 eggs are collected from one cycle (from women 35 or under with a normal amount of eggs in her ovary).
- About 80-90% of the eggs may survive being thawed.
- About 50-70% of the eggs may fertilise and create embryos.
- About 79-80% of the embryos may develop into good quality embryos.
- From the good quality embryos, a single embryo may have a 25-35% chance of developing into a pregnancy.
The egg freezing process is very effective if you begin in your 20s or early 30s.
How much time can this buy you?
Egg freezing does not guarantee a pregnancy, but storing 20-30 eggs before a woman turns 35 may give a good chance at a pregnancy.
If you want a family in future but are not able to have one now, egg freezing may offer you an opportunity to do this in the future. If you are in a new relationship it may provide some relief from committing to starting family if you or your partner are not ready.
What should you consider if you choose to freeze your eggs?
While egg harvesting can provide hope to women wishing to conceive in the future, it is not a guarantee that you will conceive. Why freeze eggs if it doesn’t guarantee a future pregnancy? The chances of conception are still much better than they are for women trying natural pregnancies after turning 40. Egg freezing success rates are very high if you work with the right specialist and follow the right guidelines.
For women who do choose to freeze their eggs, cost may be a consideration. Medicare does not subside any of the cost and often more than one cycle is required to retrieve enough eggs for future use. If you are interested in egg harvesting, you may want to verify the costs and make sure you can afford it.
The ability to freeze your eggs doesn’t mean you should postpone having children if possible. Although egg-freezing techniques are improving and pregnancy rates with thawed eggs are comparable to fresh eggs, there is still ongoing work and research needed in this field.
Another consideration is around the number of eggs you have in your ovaries; if this is low, it may be very difficult to retrieve 10-12 eggs per round of egg collection. If this is the case, alternative options may need to be discussed and considered.
It’s also important to consider your general health and other medical issues when embarking on freezing your eggs or delaying conception. The egg freezing process is very straightforward. Feel free to consult with a specialist for additional guidance.