You can preserve your fertility for the future and do not need to worry if you do not want to start a family until your mid-30s or older
Egg freezing is a method of storing a woman’s unfertilized eggs, which are different from fertilized eggs or what we call embryos. The process usually needs an ovarian stimulation program to reproduce multiple eggs. To obtain the eggs, egg retrieval is performed under general anesthesia. After the egg retrieval, the eggs will be frozen using the same technique as that for embryos. We can freeze eggs for several years without damaging the egg quality as far as the storage temperature is still ultra-low at -196 °C.
When needed for use, the frozen eggs will be thawed and fertilized with the husband’s sperm. The aim is for the fertilized egg to develop into an embryo and be transferred back to the uterus to give the chance of pregnancy.
Why do we need to store frozen eggs for the future?
Aging human bodies and aging human oocytes run on different clocks
The best reproductive potential period for a woman is during her first 20 years; after that the reproductive ability starts to decline. The main cause of declining reproductive ability is the decreasing egg quality and increasing egg abnormality as the woman gets older. The prime time is at the age of 20 and the worst time is over 40. We can average the egg quality as being 90% normal at 20 years old and 10% normal at 40 years old. Aging decline in fertility ability
Today, women live longer and healthier than ever before. The trend of delaying pregnancy until they are ready is very common all over the world, which is why the incidence of infertility is increased due to the aging factor. Egg freezing offers women the opportunity to preserve their fertility ability as much as possible at the age of freezing and to use the frozen eggs for pregnancy at a later age.
Other clinical uses of egg freezing
- Medical health reasons, for example cancer treatment that may likely be detrimental to ovarian function
- Minimization of surplus embryos during the IVF process. Some couples may have an ethical dilemma about discarding embryos, therefore egg freezing is the alternative way to decrease the surplus embryos for freezing.
- Elective egg freezing for fertility preservation. In the case where you are not ready to start a family, freezing your eggs might help you to have more time to decide. As your egg quality, can decline as you get older, the sooner you decide to freeze your eggs the better the chance of success. The best age for egg freezing is less than 35 years old.
The clinical use of egg freezing
We can use frozen eggs for creating pregnancy by thawing the eggs, process with assisted reproduction techniques by fertilization in the laboratory, embryo culture and embryo transfer. At the time of thawing we should thaw enough eggs for usage, which may be 5–6 eggs at a time.
The survival rate after egg freezing
Due to the improvement of the egg-freezing protocol, currently the survival rate after egg freezing is high, at nearly 90%. There are some evidences suggesting that the success rate is comparable with fresh eggs used at the same age and with the same method.
- Blood screening test for sexually transmitted disease, ovarian function tests to evaluate the ovarian reserve
- Start medical injections on the second or third day of the period. The process of medication is the same as that of IVF and ICSI
- Ultrasound-guided egg retrieval under general anesthesia
- Egg freezing using the vitrification technique, which has the best survival rates
Egg freezing does not work for all women
The benefit of egg freezing is that it can delay the timing of conceiving to when a woman is older; however, egg freezing will not be suitable for all women. The most important factor is the age of the woman at the time of egg freezing. The younger the woman, the better the quality of the eggs, which is the key point. In the case of older women, the eggs can be frozen but their utilization still depends on the quality and normality of the eggs, which are age dependent. Not all frozen eggs can be used to reproduce a healthy child.
More information on the clinical use of egg freezing is available at