A magistrate has labelled a Sydney mother "wicked in the extreme" after she staged a dramatic car crash, while eight months pregnant, to obtain an insurance payout.

In March, four weeks from giving birth, Ghenoua Fadel stuffed a pillow between her unborn child and a steering wheel, then slammed her white Toyota Rav 4 into another car.

When police arrived at the rain-soaked Sydney intersection, they found two heavily damaged vehicles and a dazed Fadel reportedly suffering from stomach and back pains.

As paramedics raced to her aid, she spoke of how she missed a stop sign and then ploughed into the side of a moving car. But, far from being the victim of a major traffic accident, Fadel was acting out an elaborate insurance scam.