Astonishing images from inside the womb produced by new technology show babies apparently smiling and crying.

The breakthrough in ultra-sound techniques, known as 3D and 4D scanning, could lead to advances in baby health for a whole range of conditions, including Down's Syndrome, reports Sky News.

Captured images offering new insight into fetal behavior show babies yawning, blinking, sucking their fingers and seeming to cry and smile, the British news channel said.

Traditionally, doctors have assumed infants made facial expressions, such as smiling, only after birth by copying their mother.