A woman carrying a four-year-old boy across the road in a northwest Calgary school zone was struck by a car on Friday morning.

The accident happened in the 1200 block of Northmount Drive N.W., just east of Brentwood School, at 8:40 a.m. MT.

The woman in her 40s took the brunt of the collision and was taken to Foothills hospital in serious condition. Since then, police say a serious head injury has now put her in life-threatening condition.

The child landed briefly under the car, but was not hit by a wheel or pinned, EMS officials said.

The boy was taken to Alberta Children's Hospital in stable, non-life threatening condition.

Police said the driver was issued two tickets related to failing to yield to a pedestrian.

Based on witness accounts, speed was a factor, police said.