Description

Embryo Freezing and Thawing

The freezing of embryos provides many conveniences for couples applying for IVF treatment. The
remaining embryos after the embryo transfer are followed by the embryologists,
and if they are suitable for freezing, they are frozen and stored in liquid
nitrogen at -196 ° C with the written consent of the couple. When frozen
embryos are to be thawed, they are removed from liquid nitrogen, thawed at room
temperature, separated from the protective liquid and placed in a special
culture medium and placed in an incubator (devices where the embryos are kept). On
the same day, embryos that look good are transferred to the expectant mother.

It may not be possible for all frozen embryos to
have the same viability when thawed. However, in a good freeze-thaw
program, this rate is approximately 95%. In general, approximately 9 out
of 10 embryos frozen are transferable when thawed. In addition, the
vitality in embryos can vary from person to person, although it is rare.

Frozen embryos; If pregnancy is not achieved after IVF treatment, pregnancy is achieved and ends with a
miscarriage, or when the couple wishes for a second baby after a pregnancy, the
frozen embryos belonging to the couple are thawed and transferred. Thus,
the administration of long-lasting hormone drugs to the woman is prevented and
it provides a very convenient cost as all the necessary steps in the in vitro
fertilization process will be skipped.

In our center, embryo freezing and thawing
process is applied in large numbers and successfully. In fact, fresh
transfer is not preferred in most patients due to the developing freezing
methods and the high rate of viability.

If there is any problem of the woman during the
transfer of the embryos (for example, overexcitation of the ovaries during
hormone therapy), then all embryos are frozen, considering both the risks
endangering the patient’s life (OHSS) and the reduced chance of pregnancy due
to high hormone secretion. All embryos are frozen and can be thawed and
transferred at a safer time. Again, in case the lining of the uterus
(endometrium) is not suitable for pregnancy, the embryos are frozen and stored,
and then we prefer to transfer in another period when the uterus is better prepared.

In its center, vitrification technique is used
in the freezing embryo freezing process. Using this method, we achieve
very successful results in freezing and thawing embryos. Although
technically they can be preserved for a
much longer period of time, the period of cryopreservation of embryos in our
country has been determined as 5 years in accordance with the regulation
prepared by the Ministry of Health, Supreme Board of Assisted Reproductive
Techniques. The desire to keep it longer is evaluated by the Ministry of
Health.

How are thawed embryos transferred?

First of all, the intrauterine layer of the patient, which we call the
endometrium, is prepared with the menstruation. We do this preparation
process with natural cycle (ovulation) or estrogen-containing drugs in some
patients. We follow the follicle in the natural cycle and expect the
endometrium to thicken in its own way. Transfer is usually scheduled 2-3
days after ovulation. We monitor blood hormone levels (E2, Progesterone)
throughout this entire process. After the embryos are transferred, we
start supportive treatment with progesterone.

In the prepared cycle, we use the patches or
pills containing Estrogen. Again, we follow the uterine thickness with
ultrasound as well as the hormonal change in the blood. On average, if the
endometrium and hormonal condition are suitable, such as 16-18 days of
menstruation, we dissolve the embryos and perform the transfer process.