(Xinhua)
Updated: 2008-02-28 09:45

LONDON -- Britain will put on trial shortly a new IVF (in-vitro fertilization) technique which lets eggs develop in the womb rather than the test-tube straight after fertilization, New Scientist reported Wednesday on its website.

The new technique, that allows embryos created in the lab to be incubated inside a perforated silicon container inserted into a woman's own womb, was developed by Swiss company Anecova, according to the report.

In standard IVF, eggs harvested from a woman are fertilized in the lab and allowed to develop in an incubator for 2 to 5 days. The healthiest embryos are chosen to be transferred into the uterus. But this new technique would see fertilized eggs placed in a device which is then planted in the womb. After a few days the device is taken out and the embryo deemed to have the best chances of survival reimplanted.

The new device ("silicon womb") that holds test-tube embryos inside the womb to expose them to more natural conditions provides a more natural environment and may produce better quality embryos and reduce the need to harvest so many eggs from infertile women, according to researchers.

The silicon capsule is about 5 millimeters long and less than a millimeter wide with its walls being perforated with 360 holes, each around 40 microns across. After embryos have been loaded inside, the ends are sealed and the container is connected to a flexible wire that holds the device inside the uterus. A thread trails through the cervix to allow it to be recovered later on.

With encouraging results from a small trial in Belgium, British fertility group CARE Fertility in Nottingham starts from Wednesday recruiting 40 women for the trials, the report said.

Each woman will have between 8 and 12 eggs harvested, then half their embryos incubated in the lab, and the other half inside the new device.

The trial in Belgium suggests the embryos produced in vivo rather than in vitro are of a higher quality, therefore having a better chance of survival.

Researchers at the CARE Fertility group who are carrying out the study are keen to find out whether these embryos grown by the technique have fewer chromosomal abnormalities, in addition to establishing whether the technique improves the chances of pregnancy.

"We have often wondered whether the rate of abnormality is higher with in vitro embryos, but we have never been able to establish this," said Fishel who expressed his belief that embryos grown in the device will be more resilient, meaning fewer eggs may need to be harvested from women to achieve a successful pregnancy.

Care Fertility hopes to have an initial results by May or June, and a clearer picture of how successful the technique is by the end of year.