Two newborn babies have been found in a cardboard box in the car park of a Birmingham Hospital.
The boy and girl - named Holly and Joseph by the hospital - were found on Tuesday morning at the Heartlands Hospital in Bordesley Green.
Medical staff discovered an infection in the placenta of the twins and are running tests to see what it could be.
As a result, the hospital said it is urgent the mother comes forward and have issued an appeal to her.
The hospital said the twins are only hours old and were very cold when they were found. Holly is believed to have needed medical treatment.
Det Ch Ins David Wallbank said: "The first thing I want to do is reassure the mother that the babies are okay. They are in the hospital and are receiving appropriate medical treatment."
They are bright and alert and behaving as you would expect newborn babies to behave
Faye Baillie - head of midwifery
He added there could be a chance the mother has an infection which requires serious medical attention.
"You need to get yourself to a doctor or hospital urgently to have that seen to and have yourself looked after," he appealed to her.
Head of midwifery Faye Baillie said: "They are both in incubators, they are breathing on their own, and they have not had anything to feed yet but they have a drip up to give them the fluids they need.
"They are very small but quite bright and alert and they are behaving as you would expect newborn babies to behave.
"They look stable and look well at the moment but it is early days yet.
"Within the next 24 hours we will know any problems they may have in the future. They are not showing any signs of infection at the moment."
The twins were discovered by hospital security guards wrapped in a sleeping bag inside a cardboard box in the hospital car park at 0920 GMT on Tuesday.
Holly weighed 4lb 5oz, while Joseph weighed 6lbs 13oz.
Police are examining CCTV footage in a bid to trace the parents of the babies.