Freezing eggs, embryo test experimental: U.S. group

WASHINGTON (Reuters) - Two experimental fertility procedures -- preserving a woman's eggs by freezing them and testing an embryo for genetic flaws by sampling a single cell -- remain unproven, the American Society for Reproductive Medicine advised on Tuesday.

The group recommended comprehensive counseling for any women seeking egg-freezing services, even though some studies have shown that healthy babies have been born using frozen eggs or ovarian tissue.

A few clinics are advertising these procedures and news reports have been describing them, but the group said women should know they are far from routine.

"With any new technology it is vital that patients understand completely what the process entails and the likelihood of a successful outcome," said Dr. Marc Fritz, chair of the ASRM Practice Committee.

A few reports have shown that a young girl or woman can have her eggs, or in some cases ovarian tissue, frozen ahead of cancer treatment or other procedures that may destroy fertility.

But the society, which is meeting in Washington, said that the currently available data are too limited to allow egg freezing to be considered an established medical treatment. No numbers on how many women have tried the technique were available.

Human eggs are more fragile than human embryos, which are now commonly frozen for years before use.

ASRM, a group that includes fertility doctors, also said a growing practice called preimplantation genetic testing remains experimental.

This testing, done on embryos created in lab dishes via in vitro fertilization or IVF, involves the removal of one or more cells to check for genetic problems before the embryo is implanted in the mother's womb.

It is standard for checking for genetic diseases such as cystic fibrosis, a fatal and incurable condition caused by a single mutated gene.

But the ASRM said evidence did not support the use of the procedure to improve the odds of pregnancy for an older woman, or to reduce the rate of miscarriages.

"The use of preimplantation genetic screening for chromosomal problems may one day become an essential component of infertility therapy, but for now, available evidence does not support its effectiveness and common usage," ASRM president Dr. Steven Ory said in a statement.