The results are expected to become part of the debate on British abortion law, The Telegraph reported. Parliament is considering changing the 24-week limit in England, Scotland and Wales that was set almost 20 years ago.

Researchers examined the survival rate for infants in the neonatal unit at University College London Hospital who were born after 22 to 25 weeks gestation. While the increases were more marked for those born at 24 and 25 weeks, there was improvement at 22 and 23 weeks as well, with four of the eight babies born at 22 weeks between 1996 and 2000 being permitted going home.

Julia Millington of the ProLife Alliance urged a change in the law. But Professor David Field, president-elect of the British Association of Perinatal Medicine, disagreed.

"The viability of premature babies and abortion are completely different arguments that have been muddled up," he said. "You either believe in abortion or you don't."