The kidnappers of Carroll, who was abducted in Baghdad on 7 January, had threatened to kill her by last Friday unless all women prisoners were released. There has been no word on her fate.
The five, among at least eight women held by US forces in Iraq, were freed along with 414 other detainees on Thursday, a US military spokesman said.
"The case of the women detainees is a legal case and it has nothing to do with the case of the American journalist," said an Iraqi Justice Ministry official, who declined to be named.
The US military said in a statement that a panel comprising US and Iraqi officials had recommended the release of the women after reviewing their cases.
The US military is holding about
14,000 security detainees
"We have released 419 women, including five women," a US military spokesman said.
The Justice Ministry had already publicised the panel's decision but until Thursday US officials were insisting no releases were imminent.
Iraqi officials have suggested Washington did not want to be seen to be giving in to the hostage-takers' demands.
The ministry has said it has been pressing the US military to release the women, calling their detention a "disgrace".
The detention of women offends many Iraqis and US forces seek to avoid it in most cases.
The US military is holding about 14,000 security detainees following the release of about 500 suspected fighters last week.
Many Iraqis resent the detentions system and say thousands are held on flimsy evidence without recourse to the law.
More than 200 foreigners and thousands of Iraqis have been kidnapped since US forces toppled Saddam Hussein three years ago. Most have been freed but dozens of foreigners have been killed.
Earlier on Thursday, Siham Faraj, a mother of 28-year-old Hala Khalid, who was arrested with her brother on 24 September during a dawn raid by US forces on their Baghdad home, said she was waiting anxiously to see her daughter and hoped it would lead to Carroll's safe release.
"I call upon the kidnappers of the American reporter to release her because she is as innocent as Hala"
Mother of female detainee Hala Khalid
"We are happy and we thank God for this blessing," Faraj told The Associated Press.
"I call upon the kidnappers of the American reporter to release her because she is as innocent as Hala."
"I wish the Americans would stop random arrests. We only want peace in this country."
Carroll is the 31st journalist to be kidnapped in Iraq since the start of the war in March 2003, according to Paris-based Reporters Sans Frontieres, a media advocacy group.