The incident is the latest in the U.S. involving stun guns, which have been used recently in several high-profile case, including on an 82-year-old woman in Chicago and on a university student in Florida who refused to yield the microphone during a forum featuring U.S. Senator John Kerry.
In this latest case, the pregnant woman went to the police department on Nov. 18 to ask officers to take custody of her 1-year-old son, said Michael Etter, Trotwood's public safety director.
The woman told the officer she was "tired of playing games" with the baby's father, Etter said. The woman refused to answer questions, became frustrated and tried to leave with the child, Etter said. The officer feared allowing her to leave could jeopardize the child, and he decided to detain her to get more information.
He said the officer grabbed the woman, got the child away from her and forced her to the ground. When she resisted being handcuffed and tried to get away, the officer used the stun gun on her, Etter said.
The woman wore a winter coat and did not tell the officer she was pregnant, Etter said. "She was totally uncooperative," he said.
The woman was arrested for obstruction and resisting arrest, Etter said. When she arrived at the jail, it was discovered that she was pregnant, and an officer took her to the hospital, he said.
The condition of the woman and the fetus was not known.
The FBI is investigating the arrest, and Etter said the police department is conducting its own probe to determine whether excessive force was used.
He said the officer remains on duty.
A report by the Justice Department's Bureau of Justice Statistics last month said arrest-related deaths involving stun guns or other conducted-energy devices are rising. From 2003-2005, there were 36 such deaths, with a jump from 3 cases in 2003 to 24 in 2005.