Fertility Preservation

The initial results of egg freezing were poor due to the freezing techniques used, however with the introduction of the newer vitrification technique excellent results are now achieved with the latest research showing that the chance of an individual egg surviving the freeze and then thaw process have risen from 65% to almost 95%.

Some studies from the United States and in the UK have suggested that using ICSI to fertilise the thawed eggs has resulted in fertilisation and pregnancy rates equal to those using fresh eggs in IVF

Egg freezing appears to be a remarkably safe procedure, to date more than 2000 babies have been born following treatment with frozen eggs and there is no evidence of any increase in birth defects or chromosome damage associated with this treatment.

In addition it should be remembered that the increased risk of chromosomal issues that are associated with increasing age ( such as downs syndrome and miscarriage) are fixed at the lower risk of the age at which the eggs were frozen. 

For the patient the major risk is of Ovarian Hyperstimulation syndrome caused by the development of too many follicles/ eggs, this may be a significant risk in younger patients who obviously wish to obtain an optimum/ maximum number off eggs for freezing. Because eggs are electively frozen this condition is often short lived and mild, but may require hospitalisation and close monitoring. The risks associated with egg collection under sedation are considered to be minimal with more than 50,000 of these procedures performed yearly in the UK without significant incident.

Human embryos can be stored successfully for many years, indeed a successful pregnancy resulted from an embryo transferred after being stored for almost 20 years, it is therefore  likely that both embryos and eggs can be stored indefinitely without detriment.

All treatment with regard to storage and use of human tissue for fertility is controlled by the HFEA, in order to store eggs, sperm or embryos the patient/ couple must undergo screening for HIV, Hepatitis B and C before storage, and must sign the consent to storage of either eggs or sperm (GS form) that allows storage for up to 55 years ( although as standard you will be advised to consent for storage for 10 years initially that can then be increased in 10 year instalments).

If you are storing embryos, You may will be required to complete the  consent to the use and storage of eggs and embryos WT form.

It should be remembered that if embryos are stored these can only be used in your treatment if your partner at the time the embryos were created continues to give his consent. If either partner changes their mind the stored embryos cannot be used for treatment and must be allowed to perish regardless of the wishes of the other partner.  

Clearly the number of eggs frozen will effect your options for treatment, the younger you are when the eggs are frozen will increase the chances of success, with success rates dropping rapidly after the age of 38 and especially if they are frozen when age 40 or more. 

Whilst success rates are different for different age groups it is suggested that each frozen egg has around a 4% chance of pregnancy.

More accurate data from the United states shows the effect of patients age and the number off eggs needed to be frozen  to give patients a 50-70% chance of subsequently  having a live birth.

If more eggs are collected then the number of embryos available for treatment are increased and the option for additional pregnancies are increased.

Clinicians try to avoid stimulating too many eggs as this risks a condition called ovarian Hyper stimulation Syndrome OHSS , Whilst this is usually mild and short lived in patients undergoing elective egg freezing clinicians will try to avoid stimulating much more than 20 eggs.

For some patients a second or even third cycle of egg freezing is therefore required to harvest adequate eggs to give a realistic chance of pregnancy.

When a women wishes to use her stored eggs or embryos she will be seen by one of our clinicians to organise a “frozen cycle” of treatment in which her menstrual cycle is coordinated and hormones are given by mouth to build the lining of the womb ready to receive the embryos. 

For frozen embryo use, one or two embryos will be removed from storage and defrosted, the surviving embryo or embryos are then placed into the womb using a special fine catheter.

If frozen eggs are used , at the appropriate time of the treatment cycle an embryologists will

remove all the eggs from the flask containing the liquid nitrogen, remove the cryoprotectant, warm the eggs and then fertilise them with donor or partner sperm using the intra cytoplasmic sperm injection (ICSI) technique. Using this method, a single sperm is injected into the centre of the egg using a glass

needle one-tenth of the width of a human hair. Fertilisation rates are the same as those for ‘fresh’

eggs at 60-80%.One or two of the resulting embryos are usually transferred back into her uterus following several days in culture after the ICSI procedure. The remaining embryos created will be observed and all suitable embryos can be “refrozen” and stored for later use.

You may find it useful to join a fertility support group or online forum for support such as those through Fertility Network UK or Fertility Friends.

You can self-refer to a counsellor at any stage of your treatment journey. Please visit our trusted counselling provider ‘Prickly Pear Therapy‘ to book an appointment online now. 

Alternatively, you can contact the clinic at any stage and request a referral. For patients requiring implications counselling, an appointment with the counsellor will be made as soon as you have decided to proceed with treatment and this should be completed before your main consultation.