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What is embryo cryopreservation?
Most women who undergo hormonal stimulation for an IVF or related procedure of assisted reproduction produce more eggs than necessary for transfer during that cycle. The extra fertilized eggs may be frozen or "cryopreserved" and stored for future transfer into the infertile woman if she does not achieve pregnancy initially. Even if pregnancy is achieved during the initial stimulated cycle, the couple can choose to transfer the extra frozen embryos even several years later in order to become pregnant again.
Unfortunately the process of freezing embryos has not been fully perfected. As many as one-half of embryos may not survive the thawing process. However, it is important to understand that the use of thawed frozen embryos offers an important avenue for achieving conception months to years after the initial egg retrieval. In general, fertilized eggs may be frozen in our program for a period not exceeding seven years.
