DONEGALTWP — Awoman five months pregnant died Monday afternoon after her car slammed into a post along Rabbit Road, authorities said.

The 12:25 p.m. crash may have occurred when Toni Schnell, 41, of Chicora suffered a heart attack, authorities said. She was pronounced dead at Butler Memorial Hospital. The unborn child did not survive.

State police are investigating the accident; however, a report was not available this morning.

An autopsy was conductedMonday night but a cause of death is still pending, according to the Butler County Coroner's Office.

A passing motorist spotted the wreck on Rabbit Road, just south of Slippery Rock Road in the eastern part of the township, and called 911.

The engine was still running, the doors were locked and the woman was unconscious, the caller told a dispatcher.

Chicora firefighters got to the crash site quickly and removed Schnell from her Chevrolet Monte Carlo, which had veered off the road and hit a post to a fence or possibly a mailbox, said Jason Miller, an assistant chief for the Chicora Volunteer Fire Department.

No one apparently witnessed the wreck.

Firefighters called in a medical helicopter, which landed in a field near the crash. But the planned flight to a Pittsburgh hospital was called off due to high winds.

The helicopter instead was diverted to Butler Memorial Hospital where she died at 1:37 p.m., according to the coroner's office.

Schnell, who was reportedly 20 weeks pregnant, is survived by her husband, DeWitt, and the couple's 6-year-old child.