AMERICAN SOCIETY FOR REPRODUCTIVE MEDICINE
Formerly The American Fertility Society

ASRM BULLETIN

Volume 6, Number 37

September 8, 2004

HIGHLIGHTS FROM FERTILITY AND STERILITY

Vol. 82, No. 3, September 2004

DOCTORS IN ITALY REPORT BIRTHS FROM FROZEN EGGS, CALL FOR FURTHER IMPROVEMENTS IN OOCYTE CRYOPRESERVATION TECHNIQUES

Egg freezing, while still experimental, offers some degree of hope to women seeking to preserve fertility prior to undergoing chemotherapy or radiation therapy and is an option for patients who do not want to create extra embryos for freezing in their IVF cycles.  In Italy, where recent legislation forbids the creation of more than three embryos in an IVF cycle and requires that all embryos be transferred, egg freezing is likely to become an important component of ART treatment.

In a study in an Italian fertility clinic, 68 couples undergoing IVF had eggs frozen- 51 couples wished to conserve eggs while avoiding the creation of extra embryos and 17 couples did not have sperm available to fertilize their eggs at the time of the retrieval.

Eighty-six thawing cycles were performed, involving 737 eggs, 37% of which survived.  The fertilization rate (intracytoplasmic sperm injection was used) for the thawed eggs was 45.4% and 104 embryos were transferred.  Fifteen clinical pregnancies were obtained, resulting in the births of 13 babies.

The slow-freezing protocol the researchers used for the eggs was identical to one that results in excellent survival when used for cleavage stage embryos.  Other studies have shown that vitrification, a rapid-freezing method, may produce high (65-70%) survival of thawed eggs and that freezing solutions with a higher concentration of sucrose greatly enhance survival rates.

Despite the low survival rates of the thawed eggs, those that fertilized developed well, with a rate of division approaching that of fresh eggs.  Resulting embryos also appeared to be of good quality, with over 97% considered suitable for transfer.

Owen Davis, MD, President of SART remarked, “As Dr. Borini and his colleagues point out, for egg freezing to become an established option in the treatment of infertility or the preservation of fertility, methods must be developed to obtain success rates similar to embryo freezing.  More work is needed to develop the most effective protocols and to evaluate their efficiency in various patient populations.”

(Borini et al, Pregnancies and births after oocyte cryopreservation, Fertility and Sterility, Vol.82, No.3, September 2004.)

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