Until the mid-2000’s egg freezing was technically a low efficiency procedure and showed a significant drop in the number of live embryos fertilised after thawing eggs and injecting them with sperm. Today embryo cryopreservation has become a routine procedure, particularly due to technical achievements in the last 4-5 years and the wider clinical use of a rapid freezing technique known as vitrification. Studies show that babies from eggs that are frozen and thawed with the vitrification technique do not present a significant increase in anomalies in comparison to natural births.
Who should have Cryopreservation?
At our clinic, egg cryopreservation is mostly used:
- To facilitate synchronisation between egg cell donor and recipient in donation treatments;
- In case of couples who can produce a very small number of eggs, to increase the number of egg cells to undergo fertilisation and therefore increase chances of conception;
- For social indications (postponing pregnancy due to career concerns, or concern over losing fertility etc.);
- To maintain fertility before cancer patients undergo chemotherapy/radiotherapy treatment.
How is the procedure performed?
The preparation for IVF treatment is also needed when looking to freeze eggs, so on day 2 or 3 of a female`s period the stimulation process is begun. A series of hormone injections begin and encourage the growth of the follicles, this takes anywhere between 10-12 days with the necessary monitoring and scans. Follicle development is dependent on the female and her response to the stimulation process. Once the follicles are of a certain size, ovulation is induced with a last injection and the egg collection takes place 36 hours after the said injection. The egg collection is carried out under a mild sedation where each follicle is aspirated. Not each follicle is guaranteed to contain an egg so the aspirated fluid from the follicle is checked and the eggs selected. The selected eggs are then checked to see which are mature to be frozen, anywhere from 10-15 is ideal for freezing after one cycle.