A placenta found by a dog walker after it was discarded in woodland was from a baby boy, police said today.
The gruesome discovery was made in South Woodchester, near Stroud in Gloucestershire, shortly after 7pm on Thursday.
Gloucestershire Police, who have launched an investigation, said laboratory tests over the weekend confirmed it to be from the birth of a boy of about 20 weeks' gestation.
Further DNA testing will now be carried out, in the hope of identifying the mother.
Detective Inspector Steve Bean, of Gloucestershire Police, said: "Although we were always relatively certain the placenta was from a human, it was not until it was tested in a laboratory that we could be sure.
"The testing has now been carried out and we can say for certain that it was from a human birth. We have also had it confirmed, through DNA testing, that the placenta would be from the birth of a baby boy.
"We are continuing to investigate this discovery, and as yet have not been able to trace the mother, which has been our focus throughout.
"We would still like to hear from anyone with information about who left these items. All calls will be dealt with sensitively."
A woman was walking her dog along a track that leads from Bospin Lane to Selsley Common, when her dog disturbed a plastic bag, police said.
The bag was found to contain a bowl, a placenta and some medical equipment.
Following concern for the welfare of the mother and a very premature baby, police made an appeal for information on Friday.
Inquiries have also been made with local maternity units, however none has admitted a woman who has given birth to a baby of that age, police said.
Anyone with information is asked to ring 101 quoting incident number 433 of July 26.