Police were called to the store yesterday after a security guard on the lookout of shoplifters searched the 17-year-old girls, discovered a strong odour coming from one of their bags and found the foetus.
The girls were arrested on charges of petite larceny and criminal possession of stolen property, police said. The teenager thought to have given birth was hospitalised, and the other was questioned by police.
The medical examiner's office was performing an autopsy on the remains, and more charges could follow depending on the results.
A person who answered the phone at the home of the girl believed to have given birth had no comment. No phone number was available at the address provided by police for the second teenager.