"The law has taken all my rights away," said Diane Pretty, speaking in London with the aid of a keyboard and a computer voice synthesizer.
Her husband Brian tenderly wiped her mouth as the couple were bombarded with questions.
"I am pleased in one respect because it means I have my wife here for a bit longer," he said. "But I am very sad because her choice of when to die has been take away from her."
Pretty, 43, suffers from a motor neuron disease that has left her paralyzed from the neck down and confined to a wheelchair. Her husband said doctors had told them Diane's life expectancy was "limited to months."
The mother of two brought her case to the European court after Britain's highest appeals court ruled in November that her husband could not be guaranteed immunity from prosecution if he helped her die. Suicide is legal in Britain, but helping someone else commit suicide is a crime punishable by up to 14 years in prison.
On Monday, a seven-judge panel of the European Court of Human Rights in Strasbourg, France, sided unanimously with British authorities.
In their ruling, the judges said they "could not but be sympathetic" to Mrs. Pretty's effort to avoid "a distressing death."
However, they rejected her lawyers' claims that British laws infringed on portions of the European Convention on Human Rights guaranteeing the right to life, prohibiting inhuman or degrading treatment and protecting respect for private life.
The court said any change to the law "would seriously undermine the protection of life which (Britain's Suicide) Act was intended to safeguard."
At a news conference with his wife in London on Monday, Brian Pretty said the couple and their supporters were launching a petition to support the right to assisted suicide.
"We hope the people will sign on Diane's behalf asking the government to do something about the law to allow her to have her right to choose the way she dies," he said.
The court's judgment is considered a test case for Europe, where the Netherlands became the first country to fully legalize euthanasia on April 1. Similar legislation is expected to come into force soon in Belgium, and other countries, including Switzerland, France, Germany and Sweden, tolerate assisted suicides.
"New research ... has shown that the laws on assisted dying in the UK are the most repressive in Europe," Deborah Annetts, director of the Voluntary Euthanasia Society, which backed the Prettys, told a London news conference.
"If Diane Pretty had been born in Belgium, Switzerland, France, Germany, Sweden or Finland she would not have had to go to court."
Pretty's lawyers have three months to appeal and take the case to a 17-judge grand jury.
"We are obviously disappointed that Diane has lost her case, both for her and for other people in the same position," said Mona Arshi, her lawyer from the civil rights organization Liberty.
"We really believe the court had an opportunity to remedy a defect in current law which placed Diane and people like her in a tragic trap."
Deborah Annetts, director of Britain's Voluntary Euthanasia Society, said British laws on assisted suicide were "the most repressive in Europe." She said 90 percent of Britons supported a change in the law.
However, anti-euthanasia campaigners said Monday's ruling would put a brake on mercy killing legislation in Europe and could open the way for a legal challenge before the Strasbourg court to overturn the Dutch euthanasia laws.
"We hope that a sorry chapter of legal history has now been closed," said Andy Berry, spokesman for the campaign group Alert. "People who are severely disabled are very vulnerable and society should protect them, not kill them."
"This judgment accords absolute pre-eminence to the right to life. It emphatically rejects any right to die," said Bruno Quinatavalle, of Britain's ProLife Alliance.
In a related case, Britain's Department of Health said another paralyzed woman who won a landmark case giving her the legal right to terminate life-sustaining medical treatment had died after being taken off a ventilator.
A ruling from Britain's High Court last month said the 43-year-old woman, identified only as B, had the right to refuse such treatment. She died Wednesday, the British Health Department said. The case was the first in Britain in which a mentally competent patient had applied for the right to end life-sustaining treatment.
Brian Pretty said refusing medication was not an option for his wife, since the drugs she takes are to control her pain rather than keeping her disease in check.