A more natural approach to IVF that allows embryos to grow in the womb almost immediately after conception is to be offered to British couples for the first time.

The Care fertility unit in Nottingham is recruiting 40 women for the world’s first clinical trial of the procedure, which intends to transform infertility treatment by exploiting the natural environment in which embryos develop.

In conventional IVF, a woman’s eggs are fertilised with her partner’s sperm in the laboratory, and the resulting embryos are incubated in a Petri dish containing nutrients and hormones for three days until they are ready to be transferred to the womb.

In the new technique, half of the women’s embryos are cultured in-vitro as usual, but the other half will be placed in a newly developed container that will be inserted into the womb. This sealed straw-like device, which is less than 1mm (1/25 of an inch) in diameter and 10mm long, is printed with hundreds of tiny holes, which are large enough to allow the womb’s nutrients to bathe the embryos but too small to allow the embryos to escape.

After three days of development, the straw is removed and the best one or two embryos are returned to the womb. The hope is that their quality will be improved by having been grown in their natural environment, enhancing the chances of pregnancy.

The in-vivo development (IVD) technique, which uses a device made by a Swiss company, Anecova, has achieved promising results in a pilot project in Belgium, which led to two births.

The Nottingham research will form part of the first formal patient trial, which is being conducted at five European centres. Simon Fishel, managing director of the Care fertility group, said that IVD had the potential to deliver great improvements in conception rates, while also making IVF more natural. “It may be a new era, that’s why I think this is really exciting,” he said. “When Anecova approached me I immediately saw the potential. It could bring women back into the position of nurturing their embryos from the moment of conception, which is a wonderful idea.”

The chemical bath supplied by the womb will be superior to anything that scientists can concoct in the laboratory to nourish early-stage embryos, Dr Fishel said. “It is just intuitive that using the womb should be better. We have never been able to work out 100 per cent which nutrients, hormones and other chemicals are secreted in the reproductive tract, and we don’t know if the culture media we use are optimal. It must be right to use the womb if you can: what happens inside the body is as a matter of fact normal and routine.”

Martin Velasco, chief executive of Anecova, said: “It is as close to nature as assisted reproduction technology can get.”

Patients who enrol in the Nottingham trial will receive a discount of £750 on the clinic’s usual fee of between £2,500 and £3,500, as well as free genetic testing for their embryos.

For couples to be eligible, the woman must be under 37 and child-less, with a body mass index of between 19 and 29 and no known uterine or hormonal abnormalities. She must also have had no more than two unsuccessful attempts at IVF in the past. Men with fertility problems are eligible, but not if they have a very low sperm count.

Embryos cultured by IVD and by conventional methods will be tested and compared for genetic quality before transfer to the womb. “The trial is designed so it does not compromise the patient’s chances of pregnancy,” Dr Fishel said. “If the embryos that look best are in the in-vitro group, they are the ones that go back.”

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