The measure, which must still get a final ruling from the city's mayor, is thought to be the first of its kind in the nation.
Council President Stephanie Rawlings-Blake, a Democrat who sponsored the bill, called the vote a victory for women's well-being. She cited a study by an advocacy group indicating that women have been misled at pregnancy centers that provide counseling, clothing and food for expectant mothers -- but not abortions.
"It's a step toward making sure that women have the information they need to make the right decision for their health and their future," Rawlings-Blake said.
But those who oppose abortion say the bill unfairly targets centers that provide information and assistance to poor women.
"The thing that's most disappointing about it is not the particular signs that are put up or the particular bill itself, but the message that it sends," said Maryland Right to Life legislative director Jeffrey D. Meister. "This is the first time in the United States that any elected body has chosen to vote to condemn pregnancy centers."