London: Babies in the womb develop a range of facial movements which can be identified as laughing and crying, research shows.
Study author Nadja Reissland from Durham University said: "We have found so much more than we expected. We knew that the baby blinks before birth and that some research has identified scowling before birth."
The research group examined video-taped feotal facial movements obtained by ultrasound machines in the later stages of pregnancy, according to a Durham statement.
They recorded the same foetuses after they had been found to be healthy at their 20 week scan, several times between 24 and 36 weeks of gestation. They found that facial movements become more complex over time.
Foetuses in the first stage of observation (24 weeks) were able to move one muscle in their face at a time. They would for example stretch their lips or open their mouth.
By 35 weeks, foetuses combined a number of facial muscle movements, combining for example lip stretch, lowering of the eyebrows, turning isolated movements into recognisable and increasingly complex expressions.
Professor Brian Francis, study author and mathematician at Lancaster University, said: "This research has for the first time demonstrated that in healthy foetuses there is a developmental progression from simple to complex facial movements."
The development of facial expressions means that at birth the baby has already developed the facial movements to accompany crying and laughing.