Egg freezing in IVF holds promise.(News)

BOLOGNA, ITALY -- Human oocyte-freezing techniques are improving so rapidly that this procedure soon may be incorporated into routine in vitro fertilization cycles, experts predicted at an international meeting on human oocyte cryopreservation.

Currently, most oocyte freezing is done for cancer patients and other women who face potentially sterilizing chemotherapy treatments. And it is beginning to be offered for fertility preservation in young, healthy women worried about their biological clock.

But extending its application to the general in vitro fertilization (IVF) population could increase the flexibility of IVF; oocytes could be frozen rather than discarded in cycles that have to be cancelled because of ovarian hyperstimulation syndrome or the absence of a sperm sample. Oocyte cryopreservation could also overcome some legal and ethical dilemmas posed by embryo freezing, they said.

Until now, oocyte freezing has not been a satisfactory alternative to embryo freezing, because oocytes are more fragile than embryos and thus less likely to survive after being thawed.

But recent technological improvements have made oocyte freezing a much more viable option, though there is still much debate over the merits of various freezing and thawing methods and of cryoprotective and culture solutions.

"Oocyte freezing will become a standard part of IVF within 5 years worldwide," predicted Giovanni Battista La Sala, M.D., whose clinic at Santa Maria Nuova Hospital in Reggio Emilia, Italy, is the first in the world to incorporate the procedure into all standard IVF cycles. Under the protocol, patients have three of their oocytes fertilized, and the resulting embryos are transferred to the uterus. The remaining oocytes that have been retrieved are frozen and stored for future use, he told this newspaper.

Italy has always been at the forefront of oocyte-freezing research, and its efforts in this field have intensified in the last year after the introduction of Italian legislation that bans embryo freezing and restricts standard IVF to the creation of no more than three embryos.