If left to proceed unchecked, it could mean that growth is stunted as the body receives chemical signals telling it to switch off further height gain.

BBC: NEWS | Health | Gene 'decides timing of puberty'

The findings highlight the importance of monitoring a baby's weight and height gain during the first few weeks and months, but not creating anxiety with parents of slow-growing babies, said study leader Prof Alan Emond from the University of Bristol.

BBC: Slow-growing babies 'catch-up' by teens

In the Albula Valley the track spirals to gain height, and around the austere grandeur of the Bernina Pass becomes one of the world's steepest narrow-gauge railways.

BBC: Swiss movement