Pregnant Pause

These beautiful balls of cells are mouse embryos in culture, about four days after fertilisation. If transferred to a mother, it would take approximately 16 more days for them to develop and be born. If kept in culture, they would die in a day or two. That is, unless they hibernate. Indeed, scientists have recently discovered – quite by accident – that they can put cultured mouse embryos into suspended animation for up to four weeks. The researchers had been studying the effects of growth factor inhibition in mouse embryos, but had not expected development to simply pause, nor for it to restart once the inhibitor was removed. But restart it did, and the reanimated embryos, transferred to a mother, went on to develop as normal. Human embryos also deteriorate rapidly in culture. It’s therefore hoped that this serendipitous discovery might translate into ways to improve embryo viability for assisted reproduction in people.

Written by Ruth Williams

Ruth Williams

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Ruth is a freelance science journalist based in the US. She's a regular correspondent for The Scientist, and her work has appeared in The Lancet, Nature, Scientific American Mind, BBC Focus and elsewhere. Twitter @rooph

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• Image courtesy of the Ramalho-Santos lab, University of California, San Francisco
• Eli and Edythe Broad Center of Regeneration Medicine and Stem Cell Research, Center for Reproductive Sciences and Diabetes Center, University of California San Francisco, San Francisco, CA, USA
• Image copyright held by original authors
• Research published in Nature, November 2016