A woman鈥檚 own uterus could be used as an incubator for her IVF embryos before they are removed and chosen for pregnancy. There are early signs that the method could give higher pregnancy rates than standard IVF.
The new approach, developed by Swiss company Anecova, involves placing early embryos inside the womb in a tiny porous chamber to let them get nutrients and signalling chemicals, like hormones, from their mother. After five days, the chamber is pulled out through the vagina by a cord so the best embryo can be selected in the lab for re-implanting.
The embryos have to be in a removable device, because with IVF聽the aim is to create multiple embryos but implant only one or two at a time, freezing the rest.
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Normally 鈥渢est-tube babies鈥� are made not in a test-tube but in a dish. Sperm are placed alongside eggs and any resulting embryos grow in the dish for five or six days. Then the best-developed one or two embryos are put into the woman鈥檚 uterus.
But there are concerns that embryos may be harmed by growing in the lab for their first few days. Studies so far suggest that children born by IVF are healthy, but the unnatural environment of a dish could be part of the reason why so many implanted embryos fail to lead to pregnancy: the success rate is less than 30 per cent per IVF cycle, even for younger women.
Mimicking nature
So Anecova is aiming to make the embryo鈥檚 first days mimic more closely what happens in nature. In a recent trial, 68 couples with fertility problems tried Anecova鈥檚 method, although used the device for just 18 hours to be cautious. Each woman had an average of 13 eggs retrieved for fertilisation.
Half of the resulting embryos were grown in a dish as normal. The other half were placed in the porous chamber, which was put into the mother for 18 hours and withdrawn so that the embryos could go into a dish like the control group. The best-developed embryos were selected for implantation regardless of how they had been made.
The two methods gave similar results by most measures, such as fertilisation rate, but the pregnancy rate was 81 per cent with the Anecova鈥檚 approach, compared with 56 per cent for the standard one. Anecova presented the results at the conference in Birmingham this month
In a small trial like this, that wasn鈥檛 a big enough statistical difference to conclude the device was better, but the results are promising, says Karen Schnauffer at the Centre for Reproductive Health in Daresbury, UK, who isn鈥檛 connected to the manufacturer.
Martin Velasco at Anecova says there are also psychological benefits as some women like to feel they are looking after their embryos. 鈥淵ou should see the faces of patients when they understand they can go home with their embryos.鈥�
The device is already being used at some European fertility clinics for the 18-hour period, and the firm will this year start a trial of using it for two days, and will progressively extend this to five days.
