AN ELDERLY jazz singer will spend no time in prison after being convicted of killing a pregnant woman and her unborn child after she panicked while behind the wheel and lost control of her car at a busy Brisbane festival.

Clare Hansson, 78, pleaded guilty to a charge of dangerous driving causing the death of the heavily-pregnant Kerryn Ann Blucher at the Cleveland Showgrounds in Brisbane in late 2012.

The court heard Ms Hansson lost control of her car as she tried to leave the Redland Springs Festival, knocking through two sets of bollards and hitting Mrs Blucher.

The 33-year-old mother and her unborn daughter Olivia were killed in front of husband, Vaughan, and daughter Kiara, now 3.

At 36 weeks pregnant, Mrs Blucher was due to have a baby shower the day after her death.

Family contacted relatives and friends to give the devastating reason why the celebration had to be cancelled.

Her husband read out a victim impact statement to the court, describing his loneliness, isolation and the loss of his job so he could focus on raising his daughter alone.

The redheaded grandmother appeared frail when arriving at the court, receiving support from friends ahead of her matter being called at Brisbane District Court on Tuesday.

Judge Julie Ryrie said this was a devastating double tragedy.

Judge Ryrie sentenced Mrs Hansson to four years in prison, wholly suspended for four years, with an absolute disqualification of her licence.