A US federal appeals court says three Seattle police officers were justified when they used a stun gun on a pregnant mother who refused to sign a traffic ticket.

Malaika Brooks was driving her son to school in 2004 when she was stopped for exceeding the speed limit.

The officers used a Taser three times when she refused to get out of her car.

A panel of judges ruled 2-1 the officers were justified in using force because Brooks could have picked her keys up off the floor, started the car and driven away.