Female Fertility Preservation

Fertility preservation refers to the process of freezing a woman's eggs, her embryos, or her ovarian tissue. This may give her the potential to conceive in the future should she be unable to become pregnant naturally. If you think you may have trouble conceiving in the future, fertility preservation may be an option for you to consider. Many factors can limit a woman's ability to conceive, including:

Planned surgery to remove the ovaries
Chemotherapy that can damage eggs
Radiation therapy to the pelvis
Medications that can damage eggs
Genetic causes of rapidly decreasing egg numbers
Advancing age

A decline in available eggs is a very common cause of infertility. Women are born with their life-long supply of eggs and as they age their reserve of eggs naturally diminishes each month. When a woman no longer has any viable eggs left she enters the menopause.

Cancer treatments like chemotherapy, radiotherapy, and surgery can speed up the natural decline in available eggs, thereby reducing or destroying the egg reserve. The risk of being infertile after cancer treatment depends upon the type of treatment, the woman's fertility before treatment, and her age. A cancer specialist can provide an estimate of the likelihood that chemotherapy and/or radiotherapy will decrease fertility.

There are three options that may be available for female fertility preservation. These are embryo freezing, egg freezing, and ovarian tissue freezing. At Bubtree we understand that these options may not be ideal or what every woman would choose, and we would be happy to discuss all options. For some women/couples other choices including donor egg or donor embryo therapy, adoption or childlessness might be preferable.

Embryo Freezing (Cryopreservation)

Embryo freezing involves a procedure called in-vitro fertilization (IVF) where eggs are fertilized with sperm in a laboratory, and then the resulting embryos are frozen (cryopreserved). IVF can be performed using either a male partner's or a donor's sperm.

The ovaries would be stimulated to produce more eggs than usual using medication. The medication would be taken daily for about 12 days. Blood tests and ultrasound examinations would be used to monitor the growth of the follicles (the fluid-filled sacs in the ovaries that contain maturing eggs). Once these follicles are mature, they would be drained through the top of the vagina using a needle guided by ultrasound. This procedure takes approximately 20 minutes, and is usually done under anaesthetic (although conscious sedation is an option). A microscope is used to search the fluid for the eggs, and then these eggs are fertilized in the laboratory with sperm from a partner or a donor. Embryos that develop successfully are then frozen for future use, and often a number of embryos are obtained and frozen from an IVF cycle. For more information on how this is done please refer to our IVF web page.

For women who have cancer IVF and embryo freezing are performed before starting cancer treatment. Depending upon where a woman is in her menstrual cycle this would require around a four to six week delay before commencing her cancer treatment.

When the woman is ready to use her frozen embryos, she may have to take medication to help develop the lining of her uterus in preparation for embryo implantation (particularly if she is menopausal), or it may be possible to do a transfer in a natural menstrual cycle.

Of embryos that have been developed to the day five stage (blastocyst) each embryo has about an 85% chance of surviving the thawing process and being ready for transfer into the woman's uterus. Pregnancy rates are approximately 30% per single embryo transfer, although this will vary with the quality of the embryos and the woman's age at the time they were frozen.

As per Australian government protocols, embryos can be stored for up to 5 years, after which approval from the clinic must be sought for an extension of storage. Please remember to advise the clinic immediately of any change of address or circumstances if you have frozen embryos in storage. Storage accounts are sent out every 6 months.

Egg Freezing

Egg freezing is an experimental fertility preservation option for women who do not have a partner, do not want to use donor sperm, or have ethical or religious objections to embryo freezing. The process of egg freezing is similar to embryo freezing, as outlined above. A Fertility Specialist removes the eggs after around 12 days of hormone injections, and then the eggs are frozen for future use. For women who have cancer this may require a two to four week delay in order to freeze eggs before beginning cancer treatment, depending upon where they are in their menstrual cycle.

When a woman is ready to use her frozen eggs, they are thawed and the surviving eggs are fertilized with a procedure call intracytoplasmic sperm injection (ICSI), using either a partner's or a donor's sperm. The resulting embryo(s) are then transferred to her uterus, and any surplus good quality embryos can be frozen for later use.

The success of egg freezing is currently less than embryo freezing, as eggs are more delicate structures that do not freeze and thaw as well as embryos. Typically, we would hope to freeze 5-15 eggs in a cycle, of which 70% to 80% will likely survive the freeze-thaw process. In turn, we would expect 50% to 70% of the thawed eggs to fertilize. Depending upon the woman's age at the time of egg freezing, the success rate is approximately 20% to 30% each time an embryo created from a frozen egg is placed into her uterus.

As per Australian government protocols, eggs can be stored for up to 10 years, after which approval from the clinic must be sought for an extension of storage. Please remember to advise the clinic immediately of any change of address or circumstances if you have frozen eggs in storage. Storage accounts are sent out every 6 months.

Ovarian Tissue Freezing

Ovarian tissue freezing is an experimental procedure that is usually only suitable for select women who do not have time to do embryo or egg freezing or cannot use fertility medications. The success rates of ovarian tissue freezing are too early to evaluate as this technique is very new. To date, very few babies have been born worldwide as a result of this treatment.

In this process, a Fertility Specialist removes part or all of an ovary in a surgical procedure performed under general anaesthetic. No hormone stimulation is needed. The tissue that is removed is divided into thin strips which contain immature eggs. The tissue is then frozen and stored for future use.

As ovarian tissue freezing is new and very little information is available regarding this technique, women should not consider this as the only way to preserve their fertility. Women who have cancer involving their ovaries are not candidates for ovarian tissue freezing.