LONDON (Reuters) - Non-emergency caesareans double the risk of women dying or developing severe complications following the procedure, researchers said yesterday.

The study, published by the British Medical Journal, also showed that in some cases C-sections increased the risk of death to newborn babies by 70 per cent and adds to evidence on the risks of the procedure compared to vaginal births.

"The message is it is an intervention that is not clinically needed and increases problems for the mother and babies," said Jose Villar, an obstetrician at the University of Oxford, who led the study. "That is something that should be confronted."

C-sections are favoured when doctors think vaginal delivery could cause medical complications, but have become increasingly common for what would be considered normal births.

The data on nearly 100,000 births from 120 Latin American hospitals comes from a global World Health Organisation survey and marks one of the largest studies looking at C-section risks, Villar said.

In the study, about a third of the deliveries were caesarean, about the same number as European countries and the United States. The number of non-emergency C-sections approached the 15 percent rate seen in developed countries, Villar said.

"We have had reports from single hospitals but this is the first time we have looked at a large number of hospitals," Villar said in a telephone interview.

The research showed that complications from C-sections doubled the risk of dying or severe complications, such as hysterectomies, blood transfusions, or admission to intensive care regardless of age, medical history, or where the baby was born.

The procedure upped the chances of a newborn landing in intensive care while the risk of death was 70 percent higher for babies born head first from both elective and non-elective C-sections, the researchers found.