The accident occurred at about 6:08 a.m., according to Cameron Roden, a spokesman for the Utah Highway Patrol.
"It happened right at the overpass going into Home Depot," Roden said. "Witnesses stated that the Cavalier heading westbound started to drift to the left, correct back to the right and went sideways through the median and up onto the eastbound lanes where it was struck by the Jeep heading eastbound. It was a broadside-type accident."
Heber resident Yessica Hunda, 18, who was driving the Cavalier, and Heber resident Roujine R. Ballao, 21, a passenger in the car, died at the scene, Roden said.
They were traveling from the Heber area, he said.
"The female was about seven months pregnant and they lost the unborn child," he said. "I'm not exactly sure what the life-saving efforts were for the child."
The Jeep was driven by Cottonwood Heights resident Daniel J. Kormylo, 66, Roden said, adding that Kormylo and his son, 29-year-old Daniel G. Kormylo of Salt Lake City, a passenger in the sport utility vehicle, are expected to survive the crash.
They were taken to University Hospital, Roden said.
Investigators were not sure this week what caused the woman to lose control of her vehicle.