Babies born very prematurely are no more likely to survive than in the early 1990s, despite more intensive treatment, according to a British study released Thursday.
Experts said that although those born under 24 weeks' gestation can now be kept alive longer, their chance of dying has not fallen.
A team in Newcastle, northern England, analyzed 229 babies born in the U.K. at 22 or 23 weeks between 1993 and 2007. Of those, 210 died.
One in three who died survived longer than six hours. The length of time babies lived increased in the U.K. over the 15 years, but not the ultimate rate of survival.
But the study authors said, "Overall, survival has not changed."