The mother of a south Wales woman who died from deep vein thrombosis (DVT) after a long-haul flight is continuing her campaign for airlines to change the way they operate.

Ruth Christoffersen, from Newport, is flying to the European Parliament to call for action - the first time she has used an airplane since her daughter Emma, 28, died two years ago.

DVT victim Emma Christoffersen

Mrs Christoffersen is a leading member of a pressure group seeking to persuade air operators to conduct research into DVT and to improve conditions for passengers in the meantime.

Last month, the World Health Organisation agreed to a �1.2m study into the condition, which has repeatedly been linked to air travel, but without clear scientific proof.

But in a boost to the campaign, Sven Goran Erikson's England team were persuaded to take precautionary measures before their flight to the Far East for the World Cup finals.

The death of Emma Christoffersen in October 2000 - just hours after arriving at Heathrow from Australia - led to widespread publicity over other fatal DVT cases.

Now Mrs Christoffersen wants passengers to be given proper information while research is carried out, giving them the right to make an informed choice about flying.

She will meet on Tuesday with Labour MEP Arlene McCarthy and representatives from the Aviation Health Institute to help press their case at the European Parliament in Strasbourg.

"I am getting on a plane to take Emma's case forward and I never thought I would do it," she said. "I am flying from Heathrow and I know I will do it because Emma died."

Medical history

DVT campaigner John Smith, who chairs an all-party parliamentary group set up to investigate the causes of the condition, said he was pleased progress was being made.

The research programme will aim to identify which travellers are most at risk from DVT, which has been dubbed 'economy class syndrome'.

Factors such as past history of thrombosis, use of oral contraceptives and genetic links are among the areas to be studied.

The study will also look at the effects of alcohol consumption, leg exercises and compression stockings, as well as low cabin pressure and oxygen levels on flights.

Doctors believe cramped conditions are a factor

The research also intends to offer guidance to travellers.

The European Commission is expected to provide additional funding, with preliminary results available within a year.

More than 40 long haul airline passengers are known to have died from DVT clots.

Among them are Ms Christoffersen, Susan Mavir-Ross, from Llay in Wrexham, Thomas Lamb, from Cardiff, and policeman John Thomas from Cowbridge, south Wales.

Medical research has shown that clots develop in blood vessels deep in the legs when circulation slows.

The clots can prove fatal if they break off and are carried to the lungs, blocking the flow of blood.