What is Egg and Embryo Freezing?

Quick Bites

  • Eggs that are frozen when you are below 30 years, are effective to cause a healthy pregnancy
  • Your egg count diminishes as you age
  • Your fertility potential is protected by freezing your eggs at a younger age
  • Thawed frozen embryos are of high quality



Your fertility potential will reduce along with your age. It depends on the number of eggs that are present in your ovaries. You are said to be most fertile in your 20s and early 30s and your fertility will start to decline from mid-30s.

With advanced technology, you are given a golden chance to freeze your eggs and embryos at a younger age so that you can use them for pregnancy in future years. In this way, you are given a chance to protect your fertility when you are not ready to start a family during your peak fertile years.

  1. Egg Freezing: This is a process in which your eggs or oocytes are removed, made to freeze, and then stored in order to protect your ability to get pregnant in the future. It is also known as mature oocyte Cryopreservation, egg banking, and egg cryopreservation. Eggs that are extracted from your ovaries are allowed to freeze unfertilized and are stored for later use. These frozen eggs can then be thawed to make them mix up with sperm in a lab and then are implanted into your uterus [1].
  2. Embryo Freezing: This is a procedure that involves fertilization of your egg with the sperm and then freezing the embryos for future use in a lab. The embryo is kept in a preserved mode for the upcoming years by maintaining it at a temperature of -196 degrees Celsius. The frozen embryos can be thawed and placed in your uterus when required. The embryo can be kept in a freezing state for at least 5 years or sometimes even 10 years until it is used. This is an important part of IVF treatment and is a type of fertility preservation. It is also called embryo cryopreservation [2].

Now that we have known about egg and embryo freezing methods, we shall know the difference between egg and embryo.

  • Egg: This is a single cell that is produced by your ovaries and has the capacity to develop into a new organism when it gets fertilized with a sperm cell.
  • Embryo: This can be called an unborn child from the time of your conception until the end of the seventh week.

In this article


Why Egg and Embryo Freezing Done?

It is easy for you to get pregnant before you are 35 years but for some reason, you may wish to delay your pregnancy. As there is the availability of egg and embryo freezing options for your future pregnancy, you need not worry about postponing your pregnancy.

There is no apparent increase in birth defects in babies conceived through frozen eggs.

Egg Freezing

Egg freezing is a good chance for you if you are not ready to get pregnant now because of some reasons but you are sure to attain pregnancy sometime later.

In the egg freezing method, there is no requirement of sperm to fertilize your eggs. Your eggs are just frozen before they are fertilized. There is a need to take fertility drugs to stimulate your ovaries so that they can produce more eggs for retrieval.

You can opt for egg freezing for a variety of reasons like [3]:

  • Circumstances in which you need to take cancer treatment or any other such treatment that can affect your ability to get pregnant. Treatments like chemotherapy and radiation therapy can harm your fertility and freezing of your egg before such treatment can help you to have children of your own in the coming years.
  • when you have fertility problems or other conditions that could impact your future fertility.
  • If you are diagnosed with ovarian insufficiency, early menopause, or if you have any other conditions that can increase your chances of infertility.
  • When there is a need to undergo a surgery that may cause damage to your ovaries.
  • When you are taking any Rheumatological treatment or any such other related treatment.
  • If you have any endocrine system issues.
  • If you have any ovary related disease that can cause damage to ovaries
  • If you have any medical condition or any other situation that may affect your ability to reproduce like sickle cell anemia, any autoimmune diseases like lupus.
  • If there is a risk of premature ovarian failure due to abnormal chromosomes as seen in Turner’s syndrome and Fragile X syndrome or if there is any familial history of early menopause.
  • Any genetical mutation of ovaries that require removal of ovaries
  • If you wish to undergo IVF, you may opt for egg freezing because of religious or ethical reasons.
  • If you have any social or personal reasons for which there is a need to delay your childbearing.
  • If you are unable to find the right life partner and if you are above 30 years, then you can wish to freeze eggs to increase your chances of having a baby.

You can get pregnant by using your frozen eggs and sperm from your partner or a sperm donor, who can be a known person or anonymous. The embryo that is formed after fertilizing your egg with sperm can also be implanted in the uterus of another woman to carry the baby for you, like in gestational carrier.

Embryo Freezing

After you have successfully gone through your IVF cycle, and when there are plenty of fresh embryos left over after transfer, then you can think of freezing or cryopreserving this surplus amount of embryos.

When you choose to freeze your embryos, it means that you are allowed to store them at extremely cold temperatures using liquid nitrogen. During this extreme freezing process, all the natural biological process of the embryo is ceased. Only under such special conditions, your fertility doctor can keep your embryos dormant until you wish to have a pregnancy.

The following are the reasons to choose to freeze and store your embryos [4]:

  • If having multiple or more embryos, then you may feel like storing them rather than being destroyed.
  • If you have failed in your first IVF attempt to get pregnant, then you may feel that storing excess embryos can help you to achieve pregnancy for the second time. If frozen embryos are available then there is no need for you and your partner to go through the IVF process again.
  • If you and your partner already gave birth to your baby through IVF, and then if there are any multiple numbers of embryos leftover, they can be stored for having a second baby in the future when you like.
  • If you should take treatments like chemotherapy or radiation therapy for some kind of cancers, there are more chances of such treatments to cause a reduction or complete prevention of your ability to give birth to a baby. Then you can save and preserve your embryos before you go for such treatments.
  • If there is a higher risk of you developing severe ovarian hyperstimulation syndrome, then your doctor will advise freezing all embryos for future transfer. Hyperstimulation can be of less severity and can only stay for a shorter period when pregnancy is postponed.
  • Certain conditions like endometrial polyps, poor endometrial development, or breakthrough bleeding during the time of embryo transferring can create problems while embryo implantation procedure. During such a case, freezing your embryos is always an option for you.
  • Embryo freezing is an option if you wish to delay your pregnancy without causing the risk of further damage to your eggs. With your increasing age, your ovaries will get aged and become weak. So if you preserve your embryos they help to give you a baby when you are ready for a baby.
  • Sometimes, there is a chance that you no longer need or you may wish to donate your frozen embryos to someone else through an IVF donor program.
  • It is your wish to save your embryos and then donate them for any kind of research program.

As we have discussed the reasons as to when you may need egg or embryo freezing techniques, we will move on to know the actual process of this egg and embryo freezing.


How Egg and Embryo Freezing Done?

Both processes involve similar steps at the beginning like retrieving eggs from ovaries. For this egg collection, your doctor will perform a few tests to know whether or not you require any additional medicines or hormones to prepare your body. The fertility drugs or hormonal medicines are given to stimulate your ovaries so that more number of eggs are produced by them.

All the eggs that are retrieved may not be of the best quality. So, a collection of multiple eggs will ensure you have a healthy baby. Once your ovaries start producing eggs, they are given a time of 10 to 12 days before retrieving. After the eggs are retrieved, there starts the difference in the two processes.

Let us discuss in detail the process involved in egg and embryo freezing.

Egg Freezing process

Once you decide to get your eggs to be frozen, then there are few steps as follows that can help you [5].

They are:

  • You should search for an expert fertility clinic and highly experienced reproductive endocrinologists
  • Your Gynecologist will guide you in performing an egg freezing process which involves a series of steps. The following are the steps that are used to freeze your egg.
  • You should take birth control measures according to doctors’ advice.
  • Then you will be given hormonal injections to make your ovaries get stimulated so that they can produce more eggs.
  • Then your doctor will keep you under general anesthesia and your eggs are retrieved from ovaries. The eggs that are produced by your ovaries in a 2 week time period are retrieved by passing a slender needle through the vagina. This needle is guided by ultrasound and the required amount of eggs is collected by the doctor and they are frozen.
  • Sometime later when you decide to get pregnant, your frozen eggs are thawed, fertilized with sperm of your partner or donor sperm, if required, and then the embryo is injected back into your uterus.

Embryo Freezing Process

It is known to us that a living cell primarily contains water. When frozen, this water turns into ice and causes damage to the cell walls and structures with the cell wall of the egg. So, to protect embryos from getting damaged it is stored by using special agents called crypto protective agents CPAs.

There are two methods used by your doctor to freeze and preserve the embryos and these methods are [6]:

  1. Slow freezing method
    : In this method, your embryos are made to freeze slowly by using CPAs in increasing amounts for over 10 to 20 minutes. Then, embryos are placed in a machine that will slowly lower the temperature of the embryo minute by minute. After embryos reach frozen state, they are stored in liquid nitrogen at -321 degrees Fahrenheit or -196.1 degrees Celsius.
  2. Vitrification
    : This method involves very quick and fast freezing of your embryos by using more amounts of CPAs. First, the embryos are made to mix up with CPAs and then are immediately placed in liquid nitrogen, to prevent them from strong effects of CPAs. All this process causes the embryo to get changed into a very solid and glass-like state.

A retrospective study to evaluate the efficiency of vitrification and slow freezing for cryopreservation of human cleavage-stage embryos of 305 patients, showed an embryo survival rate of 96.9% and unchanged morphology of embryo at 91.8% [7].

Embryos can be stored for a standard period of 10 years but in some special circumstances, embryos can also be stored for up to 55 years [8]. When there is a need, frozen embryos are slowly unfrozen or thawed and are placed in special fluids to make them free of CPAs.


What is The Cost of Egg Freezing in India?

Egg freezing is a totally new technology in the field of fertility medicine and is an expensive one. The cost of egg freezing is categorized into 2 types.

  1. For egg retrieval and for freezing of eggs it may cost around Rs. 50,000 to Rs. 1,00,000.
  2. When once the eggs are frozen, then the cost to retain them in the frozen state keeps changing each year and can be around Rs. 15,000 to Rs.30,000 per year.

The success rate of egg freezing

The success rate of pregnancies with frozen eggs is highly dependent on a few factors and there is no sufficient data to calculate the exact success rates. When more healthy eggs are collected at a younger age mostly between 25 to 35 years, then there is a better chance of having pregnancy.

Egg freezing can give benefits of success when done at an earlier age. According to a study, the highest chances of live birth was seen with egg freezing when it is performed in women of less than 34 years [9].

Factors that impact the success of egg freezing are:

  • Number of eggs that are collected
  • Eggs quality during collection
  • The age at which the eggs are retrieved from your ovary.
  • The age at which you get pregnant using frozen eggs.
  • The technology that is used to freeze the eggs

Which One is Beneficial For Me-- Egg Freezing or Embryo Freezing?

In the past years, there used to be a big gap in the survival rate of frozen eggs and frozen embryos. But with advanced technology like Vitrification, this gap has been greatly reduced. Now, it is estimated that the survival rate of the frozen egg is 90% and that of frozen embryos is 95%. The process of rapid egg freezing or vitrification is said to give good success rates as given by using fresh eggs [10].

You cannot consider frozen embryos as your choice even though it has a greater survival rate over frozen eggs. This is because, if you are unmarried or if you don’t have a male partner to give sperms, then all that you can do is only to freeze your eggs. Therefore, both of the processes are used based upon your requirements and your possibilities.

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List of ReferencesHide

1 .

cancer.gov.“Egg Freezing”.cancer.gov, 02 September 2020.

2 .

cancer.gov.“Embryo Banking”.cancer.gov, 02 September 2020.

3 .

uclahealth.org.“Egg Freezing”.uclahealth.org, 02 September 2020.

4 .

clevelandclinic.org.“Embryo Cryopreservation”.clevelandclinic.org.12 May 2014.

5 .

mayoclinic.org.“Egg Freezing”.mayoclinic.org.01 Feb 2019.

6 .

womenandinfants.org.“Embryo Freezing”.womenandinfants.org, 02 September 2020.

7 .

Valojerdi Mojtaba Rezazadeh, Eftekhari-Yazdi Poopak, et al.“Vitrification versus slow freezing gives excellent survival, post warming embryo morphology and pregnancy outcomes for human cleaved embryos”.pubmed.ncbi.nlm.nih.gov.J Assist Reprod Genet. 2009 Jun;26(6):347-54.PMID:19513822.

8 .

hfea.gov.uk.“Embryo Freezing”.hfea.gov.uk.29 July 2020.

9 .

B Mesen Tolga, E Mersereau Jennifer, et al.“Optimal timing for elective egg freezing”.pubmed.ncbi.nih.gov.Fertil Steril. 2015 Jun;103(6):1551-6.e1-4.PMID:25881876.

10 .

Anderson R A, Davies M C,et al.“Elective Egg Freezing for Non-Medical Reasons: Scientific Impact Paper No. 63”.pubmed.ncbi.nih.gov.BJOG.2020 Feb 26.PMID:32102111.

Last updated on: : 09 Sep 2020

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