Three people were injured in a bizarre accident in suburban Maryland today when the driver of pickup truck apparently passed out and lost control of his vehicle, which then struck a pregnant woman and crashed into a building, police said.

A spokesman for Montgomery County Fire and Rescue, Pete Piringer, said the woman and a male bystander had "serious injuries," but he did not have details.

The incident occurred shortly after 1:30 p.m. in Rockville as the Ford Ranger pickup was traveling on Edmonston Drive approaching Rockville Pike, said Terry Treschuk, the Rockville chief of police. He said the driver, a man in his mid-twenties, told a female companion that he did not feel well and suddenly slumped over the steering wheel.

The pickup truck ran a red light, went onto Rockville Pike and struck a large box truck making a left turn onto Edmonston, Treschuk said. The pickup spun around, accelerated in the opposite direction, jumped a sidewalk, traveled 100 feet down a grassy median strip, struck a driveway curb and made an abrupt left turn, he said.

The vehicle then drove across traffic on Edmonston, went over a sidewalk and struck a woman in her twenties who was standing on the sidewalk, he said. The woman, four months pregnant, was thrown 10 feet to the side, and the pickup crashed into the front of the Tenley Building at 50 West Edmonston Dr., Treschuk said.

"The woman was unconscious for about 10 minutes until Montgomery County Fire and Rescue arrived," a police report said.

She and the pickup truck driver were taken to Suburban Hospital.

A third person, the male bystander who was standing on or beside the sidewalk, managed to jump out of the way, but sustained scrapes, abrasions and possible fractures and was also taken to the hospital, Piringer said. The female passenger of the pickup was not injured.

Treschuk said it was not immediately known why the pickup driver slumped over. An investigation is continuing, the police chief said.

Piringer said the driver apparently had "some kind of medical condition" that caused him to pass out. He did not elaborate. The driver also evidently suffered some minor injuries in the crash.

Piringer said it was not known how fast the pickup was traveling but that the crash caused "heavy damage" to the vehicle. He said both occupants were wearing seat belts.