Lexi Lacey weighed just 14oz when she was born at 26 weeks.
Her parents Chelsea Rowberry, 17, and Lee Lacey, 24, from Worcester were warned by medics that it was unlikely Lexi would survive. She was saved from the brink of death by being kept warm in a small plastic bag covered in bubble wrap.
But the youngster battled against all the odds and pulled through. She is now a happy, healthy 11-week-old baby - but still only weighs 5lb 6oz. She is the most premature baby to survive at Worcestershire Royal Hospital.
Chelsea started having contractions on June 27. When they got to the hospital, she was told that she was already 3cm dilated and she gave birth to 14oz Lexi. After the umbilical cord was removed Lexi was popped straight into the plastic bag.
Dr Andrew Gallagher, consultant paediatrician at Worcestershire Royal Hospital, said: 'When very small babies are born, to keep them warm they are placed in a plastic bag for about 30 minutes.'We pop them in feet first and their head sticks out the top of the bag so that the water can't evaporate off them very easily. It acts as a little micro-environment for them to be in before they are later transferred to the neonatal unit and placed in an incubator and the bag is removed.
'The bags come from NHS supplies and are on a roll. They are open at the top, see through and about the same size as a sandwich bag but without the sealant at the top.'
Chelsea was sent home the same day but faced an agonising wait as Lexi was transferred to Birmingham's Heartlands Hospital for specialist care for three days and to the Shrewsbury Royal Hospital for just over a week, before returning to Worcestershire Royal Hospital.
Chelsea said: 'It was really scary. The hospital would ring me up to tell me she needed a blood transfusion and she probably wouldn't make it through the night.'
Lexi has now been given the all clear but Chelsea says she still gets scared because her baby is still so small.