Nearly half of extremely premature babies who survive develop a disability or learning difficulty, a study says.
Kayelan's mother says she will deal with whatever is thrown at her
Another third had mild impairments, such as the need to wear glasses, by the time they reached six years old - double the average rate.
The Epicure study has been monitoring the development of babies born in the UK and Ireland before 26 weeks in 1995.
Researchers said the findings would help parents understand what problems their children were likely to face.
More than 1,200 babies born under 26 weeks were originally involved in the study but only 314 ever left hospital and 241 were assessed in the latest round of tests.
Special learning needs
The report, published in the New England Journal of Medicine, revealed 22% had a severe disability such as cerebral palsy, blindness or profound deafness, and a further 24% had moderate disability, such as special learning needs.
The rate of moderate or severe disability among the general population is about 1%.
The figures also revealed that more than a third of extremely premature boys had moderate to severe disabilities - 2.4 times than the number of girls.
Researchers were not able to explain what caused the disabilities, although it is thought possible adverse conditions in the womb may be the cause.
But they said they hoped research in the future would look at why some have disabilities while others do not.
Lead author Neil Marlow, professor of neonatal medicine at the University of Nottingham, said the findings would help doctors and parents understand and prepare for what sort of life a premature baby would have.
"We ought to be able to give parents accurate information so they can understand the huge burden they are taking on looking after a survivor."
But Professor Marlow added it was important to remember many premature babies had disabilities that did not severely affect their quality of life.
Kate Costeloe, a professor of paediatrics at Queen Mary University of London, who has also been involved with the Epicure study, said before the research was done there was "very little data available on what happened to extremely premature babies".
She added the major impact of the study was to provide quality information to help parents.
And Melanie Gill, whose nine-year-old daughter, Naomi, was involved in the study, said premature babies can still confound doctors' expectations.
"We were told she would never go to a mainstream school. But she is and no special help is needed - she is doing well."
Naomi, who was born when her mother was 25 weeks pregnant, has some respiratory illnesses, including asthma.
One parent of a premature baby told BBC News knowing about the risks made her determined to face them head on.
Marcia Blair, who gave birth to her son, Kayelan, three months early in December, said: "I will deal with whatever is thrown at me."
Rob Williams, chief executive of premature baby charity Bliss, welcomed the report's findings.
"They give parents more control in the decision making process."
He also said he would like to see more research done on why those with no disability or mild disability achieved such an outcome to help those more severely disabled.
And he added the public should be clear that the study was on extremely premature babies not all premature babies.
Babies born before 26 weeks represent just 2% of all the babies that go to special care wards.
The assessment at six years old follows tests that were carried out when the premature babies were 30 months old.
In the earlier tests, researchers found half had no disability at all but the rise was down to cognitive problems that became more apparent as the children became older.