Semen cryopreservation (commonly called sperm banking or sperm freezing) is a procedure to preserve sperm cells. Semen can be used successfully indefinitely after cryopreservation. For human sperm, the longest reported successful storage is 24 years.[1] It can be used for sperm donation where the recipient wants the treatment in a different time or place, or as a means of preserving fertility for men undergoing vasectomy or treatments that may compromise their fertility, such as chemotherapy, radiation therapy or surgery.

During an IVF cycle, the woman takes hormones that induce controlled ovarian stimulation in order to collect more than one oocytes.

The more oocytes are produced in the ovaries and collected by the IVF doctor, the more will be suitable to be fertilized with husband’s sperm. Consequently, the more fertilized oocytes available, the higher the chances of having very good quality embryos to be transfer.

However, what are a couple’s options if surplus embryos of good quality are available?

Cryopreservation of human embryos is currently available. Moreover, frozen-thawed embryo transfer is a very simple procedure compared to an IVF stimulated cycle because there is no need of gonadotropin administration or taking high hormone doses, avoiding in most cases even injections.

Transferred back to the uterus, achieving high implantation and pregnancy rates.

Egg freezing is a fast developing process in which oocytes are collected, frozen and stored. Later, when the woman wants to get pregnant, oocytes can be thawed, fertilized and finally transferred back into the uterus as embryos.

The oocyte is the largest cell in the human body and contains a great amount of water. During oocyte freezing, the formation of ice crystals can destroy the integrity of the cell. In order to prevent this, the oocyte must be dehydrated prior to freezing. This is done using cryoprotectants which replace most of the water within the cell and inhibit the formation of ice crystals.

Oocytes are frozen using either a slow-cooling method or a newer method known as vitrification. The latter method offers high success rates worldwide and has become the method of choice in most laboratories.