CRYOPRESERVATION: Refers to the storage of cells and tissues by cooling them to sub-zero temperatures, halting all biological activities for future use.

  • 1984: First live birth from a frozen-thawed human embryo.

  • 1986: First live birth from a frozen-thawed human oocyte.

Cells and tissues frozen in the IVF laboratory:

  • Gametes (oocyte and sperm)

  • Testicular and ovarian tissue

  • Embryos (2PN - cleavage - blastocyst)

The success of the laboratory depends on induction agents, micromanipulation techniques, and culture conditions. The success of freezing depends on the quality of the cell, the method used (Slow Freezing vs. Vitrification), and the skill of the embryologist.

Vitrification: Unlike the older "slow freezing" method, vitrification is a rapid freezing technique that turns embryos into a glass-like state instantly. This modern method provides better quality preservation and higher pregnancy rates. Embryos are stored at -196°C.

Advantages:

  • Medical: If the uterine lining (endometrium) is not ideal during the treatment cycle, all embryos can be frozen and transferred in a later, more natural cycle.

  • Comfort & Cost: Subsequent attempts are cheaper and easier, as there is no need for intensive hormone medication or egg collection (OPU).

  • Special Cases: Used in cases of OHSS (over-response to drugs), polyps, or fibroids to delay transfer until the mother's body is ready.

  • Genetic Testing: Embryos can be pooled from multiple cycles to reduce the cost of genetic screening (PGT).

Legal Duration: Embryos can be stored for up to 5 years with written consent, and this period can be extended with a petition to the Ministry of Health.

Patient Story: A Miracle Twice Frozen "I want to give hope to mothers who feel they have lost it. After several failed attempts in Istanbul, I came to Irenbe. In 2010, I had 7 healthy embryos. Two were transferred, and I had my first son at age 39. In 2013, we thawed the remaining embryos for a sibling. One embryo reached the blastocyst stage, was frozen again at -196°C, then thawed once more and transferred. Despite my busy life with a toddler, I became pregnant again. At age 41, I held my second son. Do not lose hope."