The mother of the baby who was found at a recycling plant in Scunthorpe is believed to have come forward, police have said.
The teenager rang Humberside Police in distress, reporting she was the mother of the dead baby found at Bell Waste Control in Scunthorpe.
The caller was identified as a local teenage girl. She has been taken Scunthorpe General Hospital, where she has been admitted for appropriate postnatal care.
A post-mortem examination of the baby is expected to take place to establish how the baby died.
Staff at Bell Waste Control called police after the body was discovered among items being sorted for recycling.
A spokeswoman for Humberside Police said: "Whilst it is not yet clear exactly what the circumstances of this incident are, it is believed that the baby was newborn.
"The teenage girl is now receiving the necessary care she requires and further inquiries into the circumstances of what happened will be made in due course, including a post-mortem examination of the baby which is due to take place later."