Friday, 8 November 2013

Cryopreservation in Surrogacy

Cryopreservation is a process where cells or whole tissues are preserved by cooling to low sub-zero temperatures. At these low temperatures, any biological activity, including the biochemical reactions that would lead to cell death, is effectively stopped.

Sperm Freezing

Semen can be used successfully almost indefinitely after cryopreservation. The longest reported successful storage is 21 years. It can be used for sperm donation where the recipient wants the treatment in a different time or place, or for men undergoing a vasectomy to still have the option to have children.

Oocyte cryopreservation

Oocyte cryopreservation is a new technology in which a woman’s eggs (oocytes) are extracted, frozen and stored. Later, when she is ready to become pregnant, the eggs can be thawed, fertilized, and transferred to the uterus as embryos.

Egg freezing can also be beneficial for women who, for the purpose of education, career or other reasons, desire to postpone childbearing. Freezing eggs at an early age may ensure a chance for a future pregnancy.

Additionally, women with a family history of early menopause have an interest in fertility preservation. With egg freezing, they will have a frozen store of eggs, in the likelihood that their eggs are depleted at an early age.

The egg retrieval process for oocyte cryopreservation is the same as that for in vitro fertilization. This includes one to several weeks of hormone injections that stimulate ovaries to ripen multiple eggs. When the eggs are mature, a medication to trigger ovulation is given and the eggs are removed from the body using an ultrasound-guided needle through the vagina. The procedure is usually conducted under sedation. The eggs are immediately frozen.


Embryo cryopreservation

Cryopreservation for embryos are used for embryo storage, e.g. when in vitro fertilization has resulted in more embryos than is currently needed. The benefit of cryopreservation is that a woman has an additional chance to conceive without stimulation procedure and follicular puncture. She only needs to prepare for the embryo transfer with oral medication. This process starts in the first 3 days of menstruation, lasts for two weeks and requires 1-2 US examinations.

It has no negative impact on the foetus and pregnancy. Some embryos, however, can be lost during freezing - thawing processes since not all embryos survive them. Embryo cryopreservation increases the couple's chances to conceive. It's fairly economical since preservation, unfreezing and embryo transfer costs are much lower compared to the cost of a new IVF attempt.