Police are not identifying the girl who was being treated at Magee Womens Hospital of UPMC on Thursday.
Police spokeswoman Diane Richard says the baby born Wednesday night was obviously not full-term. Results of an autopsy Thursday may determine whether charges are filed against the girl, who was not in police custody.
Richard says the girl told a friend at Brashear High School Thursday morning that she gave birth the night before, and the friend alerted school officials. School officials took the girl to the hospital and alerted her mother.
Police then found the baby wrapped in towels in the drawer of a plastic storage bin.