What is Cryopreservation?
Cryopreservation is the process of fertility preservation by freezing and storage of eggs, embryos, sperms or tissues at below zero temperature for using it at later stage. Sperms are used in fertility treatment process like intrauterine insemination (IUI) or in vitro fertilization (IVF), eggs and embryos are used in IVF.
Cryopreservation the cells are frozen and stored at a point were no biological activity exists in it. Thus, it gives the opportunity of storing it for longer period. Freezing is dangerous for living thing, and during freezing process the cells could be damaged due to intra or extra cellular ice formation which affects its chemical settings. This type of damage during phase chnage is called cryoinjury. During the process cryopreservative agents a fluid substance is added to protect and prevent cell from damage.
Egg freezing is the process in which the hormones in the body stimulate the ovary to develop and produce eggs. These unfertilized eggs are removed from the ovary, frozen and stored.
In the Embryo Freezing process the eggs are removed from the ovary and fertilized with the sperm of the patient’s partner or donor to create an embryo. This procedure of harvesting is called in vitro fertilization (IVF). This embryo is either implanted immediately or frozen and stored for later implantation. The study shows that embryos can survive the freezing process up to a 90% success rate.
In the Sperm cryopreservation process the sperm are collected from the patient either through ejaculation or if he is ill and cannot ejaculate then through sperm extraction technique and are frozen and stored for later use.
Causes for Opting Cryopreservation
The fertility of a person can be at risk due to the present ailment or its treatment procedure or after-treatment effects. There is another who wants to delay the birth of a child for financial, economic and social reasons. The following are the causes based on which an individual decides on cryopreservation –
- A person who has to go through a cancer treatment process like chemotherapy and radiotherapy might affect his/her fertility.
- A person who is suffering from non-deadly disease but the treatment of it may affect his/her fertility.
- People with genetic diseases may get their fertility affected in the future.
- Women who need to undergo surgery that might affect their ovarian tissue.
- Transgender who is planning to start hormone therapy or is planning to undergo genital reconstructive surgery.
- Women who want to delay having a child till achieving their career objectives or meeting the right person to complete their education or other reasons.
- Men whose job might affect their infertility.
- Men who choose vasectomy as a contraceptive option.
- People who are on active military duty.
When to visit a doctor?
The cryopreservation can be performed by fertility specialist at dedicated fertility clinic. If you are planning for cryopreservation process for above mentioned causes kindly visit the fertility specialist for proper and accurate guidance.
Mechanism of Cryopreservation
Following are the steps involved in the mechanism of cryopreservation –
- Selection of material – The selection of material means what matter is to be preserved. It can be an egg, embryo, sperm or a tissue.
- Adding cryoprotective agents – Cryoprotective agents are chemicals in fluid form added to the material to eliminate cryoinjury, protect the material from damage and to change its physical behavior. They are added in high concentration and are of various types with hundreds of combinations.
- Freezing - In cryopreservation freezing is cooling the matter to a point where the biological activity in its cell cease to perform and thus, can be stored indefinitely. There are two methods of freezing – slow freezing and vitrification.
- Storage – The frozen material are stored in liquid nitrogen for longevity.
- Thawing – The material stored are retrieved back through initial process of warming.
- Washing and separation of preserving agent from the material.
- After washing and separation the material is checked for its viability.
- The last step is after ensuring that material is viable and still be effective, they are implanted back from where they were taken.
In vitro fertilization (IVF) is a process in which eggs are removed from ovary and fertilized with sperm of patient’s partner or donor to create an embryo in the lab.
Cryoprotective agents are chemicals in fluid form added to the material (egg, embryo, sperm or tissue) to eliminate cryoinjury and protect the material from damage.
The material (egg, embryo, sperm or tissue) is stored in liquid nitrogen.
Sperm cryopreservation is the process where sperms are collected from the patient and is frozen and stored for later use
They are slow freezing and vitrification