A woman who caused a highway crash that killed a teenage girl was sentenced to a three-year probation period instead of jail time Tuesday, because the judge didn't want her to deliver her baby in custody.

Stephenie McNeil pleaded guilty in November to dangerous driving causing death and dangerous driving causing bodily harm.

She has admitted to falling asleep behind the wheel of a truck and causing the crash that killed Taylor McKenzie, 14, and seriously injured her parents.

The crash happened on the evening of July 26, 2017, near Smoky Lake, Alta.

At an initial sentencing hearing on May 30, Court of Queen's Bench Justice Avril Inglis learned that McNeil was expecting her second child in August.

The judge reserved her decision until June 14 to consider the implications of the pregnancy.

While reading her decision in court, Inglis said a jail term wasn't suitable in this case.

She said if McNeil were to give birth while serving a jail sentence, the baby would be apprehended by Children's Services.

Instead, Inglis imposed a three-year probation period, which included a curfew for the first 12 months, and 200 hours of community service.

The sentence was suspended, meaning McNeil could serve time in jail if she doesn't follow her conditions.

The 28-year-old also received a two-year driving prohibition.

Taylor McKenzie, 14, was described by her family as an honour student with a contagious laugh, who loved animals and music. (Supplied by family )

Taylor's parents, Joanne McKenzie and Lenord Flese, were present in court for the sentencing, along with other family members.

The family cried and was visibly upset when the judge read her decision.

Family members were heard questioning why the pregnancy was given so much consideration while they were left to deal with their grief.

The Crown prosecutor had argued for a one-year jail sentence, followed by two years of probation.

The defence had asked for 60 to 90 days in jail, to be served intermittently.

The prosecution has 30 days from the date of sentencing to seek an appeal.