Frozen embryo transfer is a new type of infertility treatment. Patients who undertake the in vitro fertilization treatment may choose to freeze the extra embryos remained after the procedure in order to use them in an ulterior IVF treatment in case the current one doesn’t succeed. The frozen embryos can be transferred into the uterus later. The operation of embryo freezing is also known as embryo cryopreservation and is a way of beating the biological clock. It is known the fact that woman can get pregnant more easily at 40 with a frozen egg in her 30s than with her 40 year-old eggs.
Short description of the egg freezing process:
The embryos can be frozen beginning from one to 5-6 days after the fertilization and they can be kept in good conditions even for 10 years.
The woman patient is given special medication in order to produce more eggs. The eggs are extracted using ultrasound guiding. Individual eggs (those that aren’t in a fluid at extraction) are kept for freezing and put in a special glass tubes.
Due to the fact that the eggs can be damaged by ice crystals that form between their cells, the specialists mix the eggs with an anti-freezing solution called cryoprotectant.
After that the glass tubes with the embryos are put in a tank filled with liquid nitrogen where they are slowly frozen, the temperature reaches -196° C.
Afterwards when the patient decides that she wants to begin the freezing embryo transfer (FET) she will have to discuss with the doctor how many embryos should be transferred into the uterus. This is a very important decision because the success of the FET depends on it. Generally 3-4 embryos are transferred two days after the ovulation.
A day before the FET procedure the eggs are removed from the freezer and thawed one by one. The thawing process takes place naturally, then the cyproprotectant solution is removed and the embryos are warmed until they reach the temperature of 37°C.
The eggs are injected with sperm and begin to transform into embryos. Afterwards the embryos implantation into the uterus can start.
The embryos transfer is a very simple and painless procedure that lasts only 15-20 minutes. The embryos are introduced into a catheter that was previously inserted into the uterus. They will be deposited on the top of the uterus.
After the embryo transfer the patient can continue the fertility medications and 12 days after the transfer a pregnancy test is performed.
In the picture below you can see how a frozen egg looks like:
The success of the FET procedure depends on the patient’s age and on the number of embryos that were transferred. Only 70% of the embryos survive the freezing process, that’s why it is very important freezing and thawing a big number of embryos before initializing the FET procedure.
The cost of frozen embryo transfer is high, around 3000$. The actual freezing costs 600$ and the maintaining of the eggs cost another 100$ per year. In addition to this the fertility medications are also expensive.
But all of these worth it considering the advantages of this procedure: women have the possibility to keep their fertility over the time by freezing their eggs at an early age, this way the motherhood can be postponed disregarding the age impediment.
Another big advantage of egg freezing have the women who are suffering from a disease that can interfere with their fertility.