Embryo Freezing Process
In vitro fertilization (IVF) is widely used technique for infertile couples to have a baby
As part of the IVF process, the woman is given drugs that cause her ovaries to produce more egg than normal. With many eggs and sperms, several embryos are often made. Then, IVF specialist will transfer 1-3 embryos into woman uterus. That means there may be some embryos left over.
What is Embryo Cryopreservation (Freezing)?
Embryo cryopreservation is a vital component of the majority of infertility programs (IVF, ICSI).
Why is Embryo Cryopreservation done?
There are several reasons when an infertile couple chooses to embryo freezing
A woman can save her embryos if she is likely to undergo any treatment / surgery.
It can provide another chance to get pregnant if the IVF process fails the first time.
The embryos could be saved for donor purpose & research work.
Freeze embryos can be use later to have second baby.
How is Embryo Cryopreservation done?
Embryo is made up of cells and cells contain water. If an embryo freezing, ice is formed between the cells which destroy the cell. To avoid this situation, an embryo is frozen with some special fluids called Cryoprotective agents (CPAs). CPAs are “antifreeze” for cells.
Merits of Embryo Cryopreservation
Healthy and viable eggs & sperm are use for harvesting embryo for cryopreservation.
Potentially decreases the number of stimulated treatment cycles needed to achieve pregnancy.
Decline the chances of congenital & genetic disorders.
It maximises the chance of a pregnancy from a single stimulated IVF cycle. Cumulative pregnancy rates with 1 stimulated cycle due to good embryo freezing rates are now as high as 70-75%.
New research shows that chances of pregnancy and success are in fact higher in a frozen embryo transfer cycle over a fresh cycle as a stimulated cycle can lead to high levels of estrogen and progesterone which may decrease receptivity of the uterine lining i.e chance of the embryo implanting in the uterus.
When is embryo cryopreservation done?
How long can embryos be stored?
The embryos are stored in sealed liquid nitrogen freezers. Embryos can be frozen in liquid nitrogen for many years.
What is success rate of Embryo Cryopreservation?
Frozen embryo transfer is as successful as fresh IVF due to high quality embryo used. According to some studies, preterm birth and low birth weight is lower when IVF specialist used frozen embryo for IVF.