A new 3D ultrasound scan has produced vivid pictures of a 12 week-old unborn baby "walking", yawning and rubbing its eyes in the womb, reported the BBC.

The new scan can provide much greater detail than the conventional ultrasound, which only produces 2D images.

The 3D scan, which records fetal movement in real time, was developed by Professor Stuart Campbell at London's Create Health Clinic.

Campbell has previously released images of unborn babies, including those babies appearing to smile, in a book called “Watch Me Grow”.

Campbell says his work shows for the first time that the unborn baby engages in complex behavior from an early stage of its development, including typical baby behavior and moods at 26 weeks, such as scratching, smiling, crying, hiccuping, and sucking.

Until recently it was thought that smiling did not start until six weeks after birth.

A selection of the photos can be seen at: http://news.bbc.co.uk/1/hi/in_pictures/3847319.stm