But experts say despite this improvement, the proportion of extremely premature babies who experience serious health problems remains unchanged.
Pregnancy normally lasts around 40 weeks. A birth is said to be premature if it happens before the 37th week of pregnancy. The more prematurely a baby is born, the higher the risk of complications.
The latest findings, published online by the British Medical Journal, come from studies that compared the outcomes of premature babies born before 27 weeks in either 2006 or 1995.
The outcomes suggest that while there have been advances in maternal and neonatal care that have increased survival odds; they have done little to improve the long-term outlook for preterm children.
This means there will be more infants growing up with lifelong health problems, say the UK researchers from large university hospitals in London.
Between 1995 and 2006, the number of admissions to neonatal intensive care units of babies born at 22-25 weeks’ gestation increased by 44 per cent, from 666 in 1995 to 1,115 in 2006.
By 2006, survival shortly after birth increased by 13 per cent – up from 40 per cent to 55 per cent – but the proportion of survivors leaving hospital with major health problems was approximately the same.
Most premature births occur after at least 28 weeks of pregnancy, which means a better chance of a good outcome.