X-Message-Number: 15762
Subject: Successful egg freezing gives hopes to infertile couples
Date: Wed, 28 Feb 2001 15:26:28 +1100

LONDON - Freezing human eggs may prove far more successful in the future
thanks to a new technique developed by Italian fertility experts, it was
reported today.

To date only about 30 babies worldwide have been born as a result of
freezing and thawing eggs since the first attempts in 1986.

The procedure is fraught with difficulty, and often ends up with the eggs,
or oocytes, disintegrating during the freezing process.

But the Italian researchers, led by Dr Rafaella Fabbri from the University
of Bologna, claim to have improved the success rate to a point where it is
comparable with normal In-Vitro Fertilisation treatment.

They achieved a vast improvement in survival and fertilised 57% of eggs
using the ICSI method of injecting a single sperm into the egg.

The key to success was to dehydrate the eggs gradually and more completely
to minimise the formation of ice crystals which can damage cell membranes.

This was done by exposing the eggs to chemical protectants for longer than
usual and doubling or even tripling the normal amount of sugar in the
freezing solution.

Doubling the sugar concentration increased egg survival from 34% to 60%,
and tripling raised it to 82%.

Dr Fabbri, whose research was reported in the journal Human Reproduction,
said: "Our next step will be to improve even further the oocyte survival
rate after thawing. But our study has established that it is possible to
cryopreserve human oocytes and that ICSI could be an efficient method of
achieving satisfactory fertilisation.

"Reassuringly, over 90% of the fertilised oocytes reached cleavage stage on
day two, which is an indication of the potential viability of the embryos,
and three-quarters of the embryos were of very good or fairly good

She hoped many centres worldwide would adopt the technique and make it a
routine practice.

"It is very important that we improve the possibilities for women to become
pregnant after having their eggs frozen. It will offer hope to women who
lose their fertility through medical treatments or who may be at risk of
premature menopause. It will also help to avoid freezing embryos and
storing excess embryos."


Chris Benatar

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