Fertility Preservation Egg freezing Q&A

Definition

Technological advances now allow women to preserve their fertility potential by freezing and storing their eggs. There are two distinct reasons for women to choose to freeze their eggs.

The first is for health reasons; in particular, for women who wish to preserve their fertility before undergoing cancer treatment.
The second is for personal and social reasons as many women delay childbearing beyond their most fertile years which increases the risk of age-related infertility.

What is egg freezing and storage?

Women who wish to freeze and store eggs are given a course of fertility drugs to stimulate the ovaries to produce a large number of eggs. When the eggs are mature they are retrieved and frozen. The method for freezing eggs varies between clinics but studies show that the most effective method for freezing eggs is a rapid method called ‘vitrification’ [1]. When a woman wants to use her frozen eggs to conceive they are thawed and those that survive are mixed with sperm. If healthy embryos develop, one or two is transferred to the uterus and any remaining embryos can be frozen for later use.

Is egg freezing and storage for me?

You may want to discuss freezing your eggs with your doctor if:
You are facing medical treatment that may affect your fertility, such as some forms of cancer treatment.
You are concerned about your fertility declining as you get older and feel you are not currently in a position to have a child.
You are at risk of premature menopause or suffer from endometriosis which involves the ovaries.

What happens when eggs are frozen?

These are the steps involved in egg freezing:

Step 1. Before you agree to the freezing and storage of your eggs, your doctor will explain the process involved, including the risks and chance of success. You should also be offered the opportunity to discuss your feelings and any concerns with a specialist counsellor.
Step 2. You will be screened for infectious diseases, including HIV and Hepatitis B and C.
Step 3. You will have a course of fertility drugs and the development of follicles (fluid filled sacs containing eggs) monitored with ultrasound examinations and blood tests.
Step 4. When the eggs are mature they are retrieved in an ultrasound guided procedure under light anaesthetic.
Step 5. The eggs are frozen and then stored in liquid nitrogen.

For how long can my eggs be stored?

From a biological point of view eggs can be stored indefinitely. However, in Victoria the legal storage time limit is 10 years after which time you can apply for an extension. You must let the Fertility Service know if you change address so that they can contact you if the storage time limit is approaching.

What is my chance of having a baby with frozen eggs?

The chance of a live birth is similar for vitrified and ‘fresh’ eggs used in IVF treatment [2]. The two most important factors that determine the chance of having a baby from frozen eggs are your age when the eggs are frozen and the number of eggs that are stored [3].
The number and quality of the eggs that develop when the ovaries are stimulated decline with increasing age. A woman in her early thirties might have 15-20 eggs available for freezing after the hormone stimulation but for women in their late thirties and early forties the number is usually much lower. Also, as women age they are more likely to have chromosomally abnormal eggs.
The number of eggs available for freezing and their quality is important because in every step there is a risk that some are lost. Of the eggs that are retrieved, some may not be suitable for freezing, some may not survive the freezing and thawing processes, and some may not fertilise or develop into normal embryos. Finally, of the embryos that are transferred, only some will result in a pregnancy and some of those pregnancies will miscarry.

What are the risks of freezing eggs?

There are women who can have an excessive response to the fertility drugs that are used to stimulate the ovaries. In rare cases this causes ovarian hyperstimulation syndrome (OHSS), a potentially serious condition.
Bleeding and infection are very rare complications of the egg retrieval procedure.
Egg freezing is still a relatively new technique and the long-term health of babies born after egg freezing is not known. However, it is reassuring that their health at birth appears to be similar to that of other children [4].

What is the cost of freezing and storing eggs?

The cost of egg freezing varies between clinics. In most cases there is no Medicare rebate for egg freezing for non-medical reasons which means that your out-of-pocket expenses can be considerable. Clinics usually charge for the management of the stimulation, the drugs used to stimulate the ovaries, the egg collection procedure, and the freezing and storage of the eggs. There will also be costs involved when you decide to use the eggs to conceive.

Important questions to ask your doctor

A study of fertility clinics in the US found that the information about egg freezing available on their websites was inadequate [5]. It is important that you are well-informed about all aspects of egg freezing before you decide to proceed.

Here are some questions you may wish to ask your doctor:

Whether the clinic uses the vitrification method to freeze eggs.
What the clinic’s success rate is for egg freezing. The best way to frame this question is by asking how many eggs have been thawed and how many live births that have resulted from these.
What YOUR chance of having a baby from frozen eggs is, considering your personal circumstances such as your age and estimated ovarian reserve (a measure of how many eggs you are likely to produce).
How many eggs you should store to have a reasonable chance of having a baby.
The approximate TOTAL cost, bearing in mind that you may need more than one stimulation and egg retrieval procedure to yield enough eggs.

References:

[1] Cobo, A., & Diaz, C. (2011). Clinical application of oocyte vitrification: a systematic review and meta-analysis of randomized controlled trials. Fertility and Sterility, 96(2), 277-285.

[2] Cobo, A., Kuwayama, M., Perez, S., Ruiz, A., Pellicer, A., & Remohi, J. (2008). Comparison of concomitant outcome achieved with fresh and cryopreserved donor oocytes vitrified by the Cryotop method. Fertility and Sterility, 89, 1657-1664.

[3] Pelin, A., H. Bang, et al. (2013). "Age-specific probability of live birth with oocyte cryopreservation: an individual patient data meta-analysis." Fertility and Sterility 100(2): 492-499.

[4] Chian, R.-C., Huang, J. Y. J., Tan, S. L., Lucena, E., Saa, A., Rojas, et al. (2008). Obstetric and perinatal outcome in 200 infants conceived from vitrified oocytes. Reproductive Biomedicine Online, 16(5), 608-610.

[5] Avraham, S., Machtinger, R., Cahan, T., Sokolov, A., Racowsky, C., & Seidman, D. S. (2014). What is the quality of information on social oocyte cryopreservation provided by websites of Society for Assisted Reproductive Technology member fertility clinics? Fertility and Sterility, 101, 222-226