Embryo Freezing

What is Embryo Freezing?

Also known as cryopreservation, embryo freezing can be defined as the process of freezing embryos obtained in a laboratory environment by fertilizing the egg taken from the mother and the sperm taken from the father in order to be used in future pregnancy attempts by applying special processes. Embryo freezing is a method that is especially preferred by couples who want to have children at an advanced age.

Generally, when more than one healthy embryo is obtained from the mother in in vitro fertilization treatment, the embryos with suitable conditions can be frozen for later evaluation. Since the maximum number of embryos that can be transferred to the mother is two, the most suitable ones can be selected and frozen if there are more embryos.

How is Embryo Freezing Done?

Embryo freezing can be performed using different methods such as slow or fast freezing. The method to be used during the embryo freezing process is determined on a person-by-person basis depending on the patient’s history, the number of embryos obtained during the procedure, the quality of the embryos and many other similar factors.

The frozen embryos are stored in special tanks containing liquid nitrogen in an environment of -196ºC. Written and verbal consent from both the mother and father candidates is required during the embryo freezing and thawing process.

Before the embryo freezing process, the embryo is obtained by fertilizing the healthy eggs taken from the mother candidate and the sperm taken from the father candidate in a laboratory environment. The resulting embryo can be frozen optionally. When the frozen embryo is to be used, the mother candidate’s intrauterine tissue must be prepared. Then the embryos are thawed and the live and high-quality ones are transferred to the uterus with the help of a catheter. The standard in vitro fertilization treatment process proceeds in the following process.

On Which Day is the Embryo Filled?

Today, if the number and quality allow, the embryo is followed until the blastocyst stage. Embryos that reach the appropriate quality are frozen on the 5th or 6th day using the vitrification technique. The reason for this is that the survival rate is very high when the embryo frozen at the blastocyst stage is thawed. Accordingly, pregnancy rates after embryo transfer can be at least as high as or even higher than applications with fresh embryos. On the other hand, embryo freezing can be performed on the cleavage stage, i.e. on the 3rd day, for expectant mothers with low reserve and limited embryo numbers.

Vitrification is a cutting-edge freezing method used for egg and embryo freezing. A rapid temperature drop is achieved with the special freezing solutions used. It is replaced by a liquid called cryopreservative. Then, the embryos are taken to a liquid nitrogen tank at -196 °C and the process is completed in a total of 3-4 minutes. The freezing period in the vitrification method is shorter than the old slow freezing technique. The survival rate after thawing can also reach almost 100% for embryos frozen at the blastocyst stage.

In our country, frozen embryos can be stored for up to 5 years according to the law prepared and enacted by the Ministry of Health. Permission must be obtained from the Ministry of Health for frozen embryos to be stored for longer than 5 years (extended by an additional 5 years). If the mother-to-be has a low or no chance of obtaining another healthy embryo, the storage period can be extended.

There are two different treatment protocols that can be applied to patients for frozen embryo transfer: medicated and non-medicated protocols.

The medicated protocol is usually used in patients with irregular menstrual periods. Transfer is performed after the patients are applied medication protocols to prepare the endometrium, which is the inner wall of the uterus, for pregnancy. In the medicated protocol, an average of 2.5 weeks is needed from menstruation.

The non-medicated protocol is usually preferred for patients with regular menstruation. The patient is called for a check-up on the 2nd or 3rd day of menstrual bleeding. Without using any medication, the developing egg sac is monitored with ultrasound with frequent follow-ups starting from 1 week. In addition, the LH, estradiol and progesterone values ​​in the blood are checked and the day of ovulation is determined. Thus, the day the embryo will be thawed and transferred is determined.

What are the Advantages of Embryo Freezing?

After successful embryo transfer in pregnancy trials, quality embryos that are not transferred and will be frozen can be frozen if the couple requests it. If embryos are frozen, pregnancy can be achieved by re-transfer in the future. If frozen embryos are used, the mother-to-be can be prepared for embryo transfer directly without the need for egg collection again. This also means that pregnancy trials are stress-free.

Embryo freezing can be done during in vitro fertilization treatment. Embryo freezing may be considered if endometrial thickening is not at a sufficient level or if the ovaries are excessively stimulated. In addition, embryo freezing can be done if there is a risk to the mother’s life in the event of embryo transfer.

Today, expectant mothers may postpone their desire to become mothers due to situations such as starting a new life or advancing in their careers. In this case, the option of embryo freezing may come to mind. In addition, embryo freezing may be an option before serious illnesses such as cancer.

What are the Embryo Freezing Prices?

Embryo freezing prices may vary depending on the freezing technique used by the center performing the freezing process and the number of embryos frozen.