More than twice as many newborn babies die in poor towns than in wealthy areas, a study has found.
Researchers at the University of Leicester looked at all neonatal deaths in England over 11 years from 1997. They said the central reasons for the disparity were congenital defects and premature births, while the key risk factors were smoking and obesity.
Some evidence shows that the gap in infant mortality between poor people and rich people in England and Wales has widened since 1997.
During the period of the research a total of 18,524 newborn babies died, although if every area's mortality rate was the same as that of the wealthiest areas, the mortality rate would have been around 40% lower, the researchers pointed out.
Four in every five of the deaths were caused either by a birth defect or premature delivery. Differences in the care of women during pregnancy and birth did not appear to be a significant contributor.
The researchers said: "Smoking, obesity and teenage pregnancy have all been the subject of long-standing public health campaigns with limited success, and the UK's suggested goals require major behavioural changes."