Oocyte Freezing
Egg freezing is a process that involves stimulation of the ovaries,Vitrification is a process by which egg freezing is done, it has better survival post thaw and improved pregnancy rates.Egg freezing is being done from 1990s for fertility preservation in women with cancer. Social freezing is offered to women under 37 Years age who want to preserve fertility for a later date.Social freezing followed by IVF and embryo transfer is advantageous to womenwho want to become pregnant at an advanced age or in the future.
It is important that women understand that there are no guaranties that egg freezing will enable them to have a baby later in life. Egg freezing give women freedom and time to choose, when they want to have a baby.
Treatment options may include IVF, in vitro maturation (IVM) or, if the sperm you are using is not of optimum quality, ICSI.
Chance of having a baby with frozen eggs: Eggs do not respond as well as embryos to freezing, and generally the resulting success rate is not as high, although this will vary from clinic to clinic. However, vitrification(a new method for egg storage) has recently been shown to improve the chance of eggs surviving the freeze-thaw process and therefore increase the success rate. Vitrification (a new method for egg storage) has recently been shown to improve the chance of eggs surviving the freeze-thaw process and therefore increase the success rate. To help boost egg production, fertility drugs are used to stimulate the ovaries to produce follicles (which contain the eggs). The developing follicles are monitored and when they are large enough, they are carefully emptied to collect the eggs that they have produced. They are collected while the patient is under sedation or general anaesthetic. To freeze the eggs, they are placed in storage in liquid nitrogen.
Risks of freezing eggs: The usual risks of using fertility drugs apply to the fertility treatment involved. Egg freezing is still a relatively new technique and not all eggs will survive the freezing and thawing process or become fertilised. It is important that taking into consideration the risks of this procedure and the likelihood of eggs surviving the process when deciding whether to store eggs for future use.
Options for girls or women having cancer treatment: Some women about to have cancer treatment are able to freeze their eggs for later use. For those who are not able to do this, freezing ovarian tissue may be an option. This involves either taking a whole ovary or small pieces of tissue from an ovary, containing eggs, which is then frozen and stored. Ovarian tissue freezing is in the very early stages of clinical use but it may be a suitable option for girls or some women wishing to preserve their fertility before undergoing cancer treatment. It may be suitable for girls who have not reached puberty yet and do not therefore have any mature eggs to collect from their ovaries for egg freezing. It may also be suitable for women who do not have enough time to undergo an egg collection before their cancer treatment commences.
Storingeggs may enable you to use them for treatment in the future in case, have a condition, or are facing medical treatment for a condition, that may affectfertility, concerned aboutfertility declining asgetting older and are not currently in a position to have a child, at risk of injury or death
The procedure for freezing eggs is as follows:
- Beforefreezing and storage ofeggs,clinician will explain the process involved, including the risks.
- Clinic should also offerthe opportunity to discuss any concerns with a specialist/ counsellor.
- Screened for infectious diseases, including HIV and hepatitis B and C.
- Written consent foreggs to be stored.
- Eggs are collected using the same procedure as for conventional IVF.
- Cryoprotectant(freezing solution) is added to protect the eggs when they are frozen.
- The eggs are frozen either by cooling them slowly or by vitrification (fast freezing and then stored in tanks of liquid nitrogen).