In many IVF or ICSI cycles people have a number of unused embryos.
It is a good idea to freeze them for use in later treatment cycles without using drugs for ovarian simulation. The chances of getting pregnant with a thawed frozen embryo are not affected by the length of time the embryo has been stored.
You may also choose to freeze embryos when you are facing medical treatment for a condition that might affect your fertility. Currently embryo freezing is the most effective way for women who to preserve their fertility.
When you decide to use your frozen embryos your doctor may suggest using a natural cycle or you are given medication to prepare the endometrium. When the endometrium is at the most receptive phase, the embryologist thaws the embryos and they are transported back to uterus.
What is freeze all policy (FAP)?
With FAP the entire group of embryos is cryopreserved and the Embryo Transfer (ET) is performed later in a natural cycle or in a cycle with hormonal replacement or endometrial priming. The potential advantage of this method is that it provides physiologic environment in which embryo transfer (ET) can occur.