Huge improvements have been made in the survival rates of premature babies, according to a new study published in the Journal of the American Medical Association.
Figures from Sweden show that thanks to medical intervention, around 70 per cent of babies born alive between 22 and 26 weeks gestation now survive past the age of one.
However, more than half of those that do survive suffer from serious health problems throughout childhood and in later life.
Sweden is known for its active treatment although doctors argue that not all extremely premature live-born infants should be kept alive at any cost.
Lead researcher Dr Karel Marsal of Lund University Hospital said: "Certainly, at 22 weeks the chance of surviving is very small, but at 23 weeks the results are much better.
"But gestational age alone is not enough to judge prognosis. We know from other studies that some of these premature babies might go on to have problems later in life and we will be monitoring them for this."
