Unborn babies have been found to 'practice' facial expressions of pain in the womb.
Scientists studied 4D images of foetuses and say it's the first time they've seen the expression - although they don't suffer any pain.
They claim it could potentially give doctors an idea of the health of the unborn baby in future.
Dr Nadja Reissland led the research at Durham University in the UK:
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The ability to show pain through facial expressions is a developmental process which helps the unborn baby prepare for life.
The research was carried out by creating scans of 15 healthy foetuses and could give doctors another index of the health of a foetus.
The study shows a foetus is capable of making simple one-dimensional expressions at 24 weeks, such as the ability to move the lips to form a smile.
By the time a Mother is 36 weeks into her pregnancy, a foetus can perform complex multi-dimensional expressions which can be recognised as showing pain.
The results show healthy foetuses 'learn' to combine the necessary facial movements before they are born.
Dr Reissland says "This suggests that we can determine the normal development of facial movements and potentially identify abnormal development too. This could then provide a further medical indication of the health of the unborn baby."
The study is due to be published in the academic journal PLOS ONE today.
