Moving ultrasound images showing 12-week-old foetuses sucking their thumbs and appearing to "walk" do not prove they have feelings and provide no scientific evidence for lowering the age limit for abortion, experts said yesterday.
The debate surrounding when unborn babies can feel - and so the age up until which they should be aborted - was reignited by 4D scans, three-dimensional images with movement, that were pioneered by Professor Stuart Campbell, former professor of obstetrics and gynaecology at King's College, London.
The moving images showed that unborn babies can stretch, kick and leap around from 12 weeks, make intricate finger movements at 15 weeks and yawn at 20 weeks. They also revealed that 18-week-old foetuses can open their eyes.
The images were used by the anti-abortion lobby to argue against the 24-week limit. But yesterday three neonatal experts warned that the scans, though "fantastic", provided no fresh scientific evidence to justify lowering the limit.
Donald Peebles, a consultant in foetal medicine at University College London, said yesterday: "The temptation is to associate foetal movements with adult movements - it's sucking its thumb because it's happy, it's walking because it's going somewhere. I think it's that step which is extraordinarily dangerous. I don't think in scientific terms these shed any new light whatsoever on the debate."
Huseyin Mehmet, a reader in developmental neurobiology at Imperial College London, said: "I worried when I saw those images. These images do not prove that those human qualities can be attributed to a foetus of 12 weeks."
John Wyatt, professor of neonatal paediatrics at University College Hospital, London, agreed that the ultrasound images made no fundamental difference to scientists' understanding of neuroscience.
But Prof Campbell, who now heads the fertility clinic Create Health Clinic, said he had recently seen images of an 18-week-old foetus making a "crying" face. He said: "This is just a piece of evidence. It's not proof but you can't just dismiss this."
