VISTA, Calif. -- A 17-year-old girl who was seven months pregnant was fatally struck by a car in Vista, authorities said Friday.

The teen was hit by a 1968 Chevy Impala in the 1500 block of North Santa Fe Avenue around 10:20 p.m. Thursday, San Diego County sheriff's Sgt. Dave Schaller said.

The Impala was traveling northbound at about 80 miles per hour when its driver lost control and the car began to slide sideways, Schaller said.

The teen was struck while walking alongside the roadway in front of her family's residence, he said. Her name was not immediately disclosed.

Two men, a woman and two girls inside the vehicle suffered minor to moderate injuries and were taken to the hospital as a precaution, according to Schaller.

The driver, 21-year-old Mark Allen Davidson, was later arrested on suspicion of two counts of vehicular manslaughter, Schaller said.