Like babies, embryos like to be rocked, too

Rocking growing embryos during IVF (in vitro fertilisation) could improve pregnancy rates among women undergoing the procedure, and decrease its risks. Scientists at the University of Michigan, US, have built a device which mimics the movement felt by embryos on their way to the uterus. When they used this during IVF with mouse embryos, they found pregnancy rates were 22 per cent higher compared to those grown statically. The research was published online in the journal Human Reproduction and was funded by the National Institutes of Health, the US Department of Agriculture, the Michigan Economic Development Corporation, the US Army Research Laboratory and the Coulter Foundation.

'By making the cells feel more at home, we get better cells, which is key to having better infertility treatment', said Shu Takayama, an associate professor in the Department of Biomedical Engineering and in macromolecular science and engineering. The rocking movement in the device is created by pulsing Braille pins, sitting underneath a thimble-sized funnel holding the embryos. The pins stimulate a flow of fluid through channels in the bottom of the funnel, copying the currents created by cilia - hair-like projections inside the body - and muscles. In the body these motions help to push fertilised eggs to the uterus and flush out waste products.

'One of our goals for years now has been to modify how we grow embryos in the lab to be more like how they grow in the human body, because we know that the human body grows them most efficiently', commented Gary Smith, co-author of the paper and associate professor in the Department of Biomedical Engineering and in macromolecular science and engineering. Presently in IVF, eggs are fertilized with sperm and left to grow for several days in a culture dish that remains still.

If similar results are found in humans, it could lead to reduced multiple pregnancies from the IVF process, its biggest risk. Professor Smith emphasised: 'We're making healthier embryos, which not only can improve pregnancy rates, but also could allow us to transfer fewer embryos per cycle and reduce the incidence of twins and triplets'. In the UK, the Human Fertilisation and Embryology Authority (HFEA) is currently campaigning to reduce multiple births, and the government wants to cut them from one in four to one in ten in IVF by 2012. Trials on humans are already underway, through the company Professor Takayama and Professor Smith founded, Incept Biosystems.

In the US, IVF currently costs around $15,000 per cycle and is often not covered by insurance. It has a success rate of about 35 per cent. 'If we could increase that, even just to 45 per cent, that's significant', said Professor Smith.