Embryo Freezing

Applications & Situations

What is embryo freezing? When is it done?

Embryos may sometimes need to be frozen during IVF treatment. Even though the freezing process is known as "resting the uterus" among the people, this is actually not done because of the need to rest the uterus. It is performed in order to increase the chance of pregnancy and to reduce the risk of OHSS most of the time, since the hormones that rise more than normal do not create suitable conditions for the embryo.

In patients with 15 or more eggs, freezing all embryos and transferring them in the following months increases the chance of pregnancy and is safer for the patient.

Today, this clinical picture called OHSS, which impairs body functions to a life-threatening extent, is very rare due to the widespread use of embryo freezing.

Conditions in which embryo freezing is required;

  • In case of OHSS (Ovarian Hyperstimulation Syndrome), overstimulation of the ovaries,
  • If PGD (Pre-Genetic Diagnosis) is planned,
  • In cases where embryo pooling is required,
  • If a surgical procedure is planned before embryo transfer due to polyp, endometrial adhesion and thinness, septum hydrosalpenx, fibroids, etc.
  • If freezing was performed for reproductive preservation before oncological treatment
  • It is performed if pregnancy is not desired immediately for social reasons.

How are Frozen Embryo Transferred?

After the first or second menstrual bleeding, in which the freezing is made, the uterus is made suitable for the embryo to be transferred, the transfer is made. For this purpose, three kinds of preparations can be made;

  • Natural Preparation;
  • Preparation by stimulating ovulation with various drugs
  • Preparation with hormone administration

Natural (Natural) Preparation:

After detecting ovulation by looking at ultrasonography and hormone levels without any medication, embryo transfer is performed by planning the appropriate environment for the embryo to attach to the uterus. It is suitable for patients who have regular menstruation and ovulation, and whose uterine lining (endometrium) thickness increases normally. It is advantageous not to use hormonal drugs. It is a safe method with a better chance of pregnancy and less chance of miscarriage. In women with regular menstruation, an average of 20 days is sufficient for preparation.

Preparation by Stimulating Ovulation:

By stimulating ovulation with Letrozole, the uterus can be prepared with the hormones secreted by the natural egg. It is preferred in patients where hormone use is risky, PCOS (Polycystic Ovary Syndrome) without natural ovulation, obesity thrombophilia risk and hormone use such as breast ca. It is monitored like natural egg tracking. If ovulation is achieved, the results are successful.

Preparation by Giving Hormone Drugs:

It is the oldest and classic application. Starting from the second day of menstruation, within 20 days, the inner layer of the uterus is thickened with hormonal drugs containing estrogen and progesterone, and embryo transfer is performed. It is the most preferred preparation method for patients whose uterine inner layer remains thin due to intrauterine adhesions. The drug dose is increased according to the patient's response.