Shocking footage from Australia has captured the moment a teenager riding a scooter tried to rob a pregnant mother on a walk with her two children.

The 37-year-old mother was walking down a laneway in Ashfield, Perth, at around 12.40pm on Monday when a 15-year-old girl approached her.

CCTV footage shows the teen dragging the mum along the concrete footpath by her hair as she clings on to her pram.

The pram falls to the ground as the desperate mother clings to it, with her two children screaming.

She suffered minor cuts and bruises but fell on her stomach, with officers concerned for her unborn child.

Western Australia Police arrested the 15-year-old shortly afterwards, alleging she was trying to steal the mother's handbag.

Extra footage showed the teen swearing at officers as they apprehended her late on Monday.

The 15-year-old was charged with one count of robbery and is expected to appear in Geraldton Magistrates Court on September 13.