The sheriff sentenced Ryan Ogilvie (21), a prisoner at Perth, to two years, four months in prison and banned him from driving for three years.

Ogilvie admitted assaulting the woman in Cardean Street, on August 22, presenting an uncapped needle and robbing her of her car and her handbag and their contents. He was on bail at the time.

Depute fiscal Vicki Bell said the victim was 22 weeks pregnant at the time. She had just returned to her car after collecting a birthday cake.

The accused got into the car and sat in the front passenger seat. He presented an uncapped needle and told her to get out.

She told him to leave her car and he said, “Leave your bag and get out of the car or I will stab you with this”.

The woman edged out of the driver’s door as Ogilvie moved over to take her place and drove off. The woman shouted to passers-by and members of the public came to her assistance and called the police.

The car was found in Crescent Lane and Ogilvie was identified from CCTV footage.

Defence agent George Donnelly said Ogilvie had drifted into the world of drug addiction and by the time of the robbery his every waking thought and action related to getting heroin.

That day he was “rattling” and noticed the woman’s handbag in the car.

He had no interest in taking the car itself but it was his recollection she put up some resistance when he opened the door and tried to take her bag.

The cap came off the needle as he pulled it from his pocket and was later found in the car, Mr Donnelly continued.

Ogilvie drove off in panic and only travelled a short distance before leaving the vehicle and making off with the bag.

It was a sign of how low he had sunk that he pawned a digital camera that was in the bag, using his own passport as identification.

At no point did he realise the woman was pregnant and he was sorry for the distress he had caused her.

“Strange as it may seem, he considered this incident has in fact saved his life because he is in no doubt that if he was not in prison heroin would have killed him,” added Mr Donnelly.

After reading a victim impact statement, Sheriff Munro described the woman as “absolutely astonishing.

“She is quite determined not to let what you did affect her,” the sheriff went on.

“She is really, really impressive, but why should she have to be, that’s really the point?”