The terms egg freezing and embryo freezing are always confused with each other. To clarify; egg freezing refers to the egg cells collected from the mother, whilst embryo freezing refers to an egg fertilised with the sperm of the father. The two freezing processes are completely different from each other.
Since the first successful pregnancy using frozen embryos in 1984, embryo freezing techniques have improved for more than 30 years, as has the rate of successful pregnancies.
In medical terms embryo freezing starts with the use of a chemical called cryoprotectant which protects the embryos from any damage. The embryos are then frozen in this solution and are stored in tanks containing liquid Nitrogen at minus196 degrees celsius in compartments dedicated to the individual patient. Liquid Nitrogen prevents the embryos from continuing cellular activity and they can be preserved for many years without deterioration.
Why opt for Embryo Freezing?
After IVF treatment is completed couples may want to keep their remaining embryos by freezing them as this guarantees them the chance of a sibling in the future. It is particularly useful when the treatment has involved egg donation, sperm donation or embryo donation as couples who want to have siblings in the future guarantee a 100% DNA match in all their children.
Patients over 35 years old can be secure in the knowledge that despite fertility decline their next baby is possible via frozen embryo transfer. In addition mothers who do not want to do another fresh cycle of IVF, or who are afraid of needles may opt for embryo freezing to avoid this whole stage of treatment.
A Frozen Embryo Transfer (FET) means couples who have already been through IVF will not have to go through the stimulation phase again which is very intense both emotionally and physically. In addition couples will not face the same monetary cost which can be one of the most challenging aspects of IVF. It is in the interest of couples who undergo IVF treatment and are left with additional high quality embryos after transfer to request embryo freezing.
Patients who will benefit from embryo freezing include:
- Those who want to have siblings.
- Those couples who want siblings with a 100% DNA match following egg donation as we use fresh eggs, and the same donor may not give eggs in the future. Similarly, in sperm donation treatment the sperm obtained from the sperm bank may not be available in the future.
- Couples who do not want to experience the same treatment costs in the unlikely event of a negative result or in the unlikely event of a miscarriage during pregnancy,
- Couples where one or both partners are likely to face Chemotherapy. The drugs used to stop the growth of cancerous cells also affects egg and sperm cells.
- Those who do not want to undergo the IVF treatment process again or those women who are afraid of needles or found the treatment process challenging.
Transfer Of Frozen Embryos
When couples want to have a baby with their frozen embryos, the following steps take place:
- On the 2nd day of her period, the mother starts taking medication in tablet form to prepare her endometrium (uterine lininng). Folic acid supplements are also recommended for vitamin supplementation during treatment.
- After 7 days on the medication, an ultrasound examination is required to look at the lining of the uterus. According to the endometirium thickness, medication doses are reviewed.
- After 12 days another ultrasound measurement is required and further medications begin to prepare the mother's uterus for pregnancy.
- On average medication is used for 16-18 days and embryo transfer is performed by Dr. Firdevs in Cyprus on around day 16.
Research shows that embryos can be frozen for 10 to 15 years with positive results, however the law set by the Cyprus Ministry of Health dictates embryos can only be stored in liquid nitrogen for a maximum of 5 years.