Detectives from the Special Victims Unit tell Action News that the mom was arrested on charges of endangering the welfare of a child and recklessly endangering another person.
The incident happened around 10:15 p.m. Sunday in the 5200 block of Pennsgrove Street.
According to investigators, the teen had put the baby in a bathtub when she heard an argument. She allegedly left the bathroom for about a minute and, when she returned, the baby was underwater and unresponsive.
The baby, said to be a boy of about 6 months old, was rushed to the hospital and remains in critical condition at Children's Hospital.