A number of small bones were discovered in a plastic bag off a towpath leading from Welbeck Lane at the Washlands Nature Reserve, in Eastmoor, last week.
The bones were spotted by a member of the public on Sunday, May 1 but were not reported to police until the following Tuesday.
Scientists and Crime Scene Investigators conducted a forensic analysis of the remains, which suggested they were of a full term new-born baby.
It is not known how long the bones may have been there but detectives say they could have been there for “a considerable amount of time.”
Detective Chief Inspector Nicola Bryar, who is leading the enquiry, said: “Investigations have been ongoing since last week into the discovery of a number of small bones, in woodland near the Southern Washlands Fishing Lake, off Welbeck Lane.
“Forensic examinations have determined the bones were those of a full term new born baby, and may have been there for a considerable amount of time.
“We are mindful that the mother of that child will have been through a traumatic ordeal and while there is no immediacy for any need for medical treatment, I am sure that some form of emotional support will be needed. “
The Homicide and Major Enquiry Team is continuing its enquiries.
And anyone who has information about the historic remains is asked to call police on 101, referencing incident number 364 of May 3.