Premature babies born after only 22 weeks in the womb or earlier should not be routinely resuscitated, according to suggested guidelines published today for parents and doctors.
It is "extremely rare" for babies born before 22 weeks to survive and only around 1% of babies born between 22 and 23 weeks survive to leave hospital, according to the Nuffield Council on Bioethics.
Guidelines put forward by the council recommend that intensive care should not be given to babies born before 22 weeks and babies born between 22 and 23 weeks should not, in normal practice, be given intensive care unless parents make a request and doctors agree.
Professor Margaret Brazier, who chaired the committee that produced the guidelines, said: "Natural instincts are to try to save all babies, even if the baby's chances of survival are low.
"However, we don't think it is always right to put a baby through the stress and pain of invasive treatment if the baby is unlikely to get any better and death is inevitable."
The report said it was "very difficult" to predict whether babies born between 23 and 24 weeks would live, die, be healthy or have disabilities later on in life.
Because of this uncertainty, the report recommends that parents, after a thorough discussion with the healthcare team, should have the final say in whether intensive care is given.
For babies born between 24 and 25 weeks, normal practice should be to give intensive care, unless the parents and the doctors agree that there is no hope of survival, or if the level of suffering outweighs the baby's interest in continuing to live, the council said.
Over 25 weeks of gestation, babies have a sufficiently high chance of surviving and low risk of developing severe disability and intensive care should normally be given.
Prof Brazier added: "We believe that the guidelines will help parents and doctors to make decisions in these very traumatic situations."
The report comes after an increase in the number of extremely premature babies being born since the 1980s.
Research into UK nationwide data, called the EPIcure study, has shown that the percentage of babies born alive in 1995 between 22 to 23 weeks who survived to leave hospital was 1%; at 23 to 24 weeks it was 11%; at 24 to 25 weeks, 26%; and 25 to 26 weeks, 44%.
Survival before 22 weeks is very rare. The Nuffield Council on Bioethics report said more recent data indicated that survival rates were higher now, although the EPIcure study still provides the only UK nationwide data available.
If an extremely premature baby survives to leave hospital, he or she may grow up with disabilities.
The same data showed that of the babies born between 23 to 24 weeks who survived, about two-thirds had moderate or severe disabilities.
By 25 to 26 weeks, two-thirds had no or mild disabilities.
The report, called Critical Care Decisions in Fetal and Neonatal Medicine, contains a number of other recommendations, including guidance on how to resolve arguments between parents and doctors over what happens to a child.
The council said it has concluded that the "active ending of life" of newborn babies should not be allowed, "no matter how serious their condition."
"The professional obligation of doctors is to preserve life where they can," it said.
The report also covers decisions made during pregnancy when abnormalities are detected in the unborn child, assessing the best interests of sick babies and areas that require further research.
The consultation over the ethical, social and legal issues has sparked an intense debate about when and whether sick babies should be allowed to die.
The Church of England, in its submission to the council, said that every life is valuable to God, but there could be rare circumstances where treatment was futile and the child should be allowed to die.
The UK has the highest rate of low-birth-weight babies in Western Europe, according to premature baby charity BLISS.
The charity said about 300 babies are born in the UK each year at 23 weeks. They have a 17% survival rate, compared with 50% for those born at 25 weeks.
There are about 250 units in the UK offering neonatal intensive care, high dependency and special care.
The Nuffield Council on Bioethics, an independent body, was established in 1991 to examine ethical questions raised by advances in biological and medical research.