There is nothing as sad in this world as the death of a child, and yet every year the most common cause of death for children aged between one month and one year is unknown. Wendy Champagne looks into every parent's nightmare.

As the treatment and prevention of other potentially fatal childhood diseases becomes more successful, Sudden Infant Death Syndrome or SIDS remains a disturbing mystery both to parents and doctors around the world.

Cot Death, as it was formerly known, claims the lives of 250 Australian children each year. The numbers have halved since the late 1980's when the British comedians Rowan Atkinson, Lenny Henry, Ben Elton, Dawn French and Jennifer Saunders conceived the high-profile Red Nose Day for a group called Comic Relief. Since then all nine SIDS Organisations in Australia have successfully adapted the concept to raise community awareness about the risk of certain childcare practices, as well as fund support programs and research into SIDS.

SIDS strikes any time, any place. No one knows the exact cause - it occurs in hospitals where trained personnel could provide resuscitation if they were aware of the situation. SIDS deaths happen day or night, in cots or car seats, prams or bassinettes - infants have even died in the arms of their parents.

Choking, vomiting or minor illnesses, vaccines or other immunisations do not cause SIDS. It is not contagious, nor is it caused by abuse or neglect. There is no apparent pain or suffering to the child in a SIDS death, but that doesn't account for much when a parent is faced with the sudden, inexplicable loss of his or her child.

Although the numbers of SIDS deaths have fallen dramatically since the awareness campaigns and the advent of Red Nose Day, organisers warn of complacency, "There are more recorded cases this year than last year," says Kaarene Fitzgerald, Director of SIDS Australia. "This indicates that some people are not getting the message about risk factors." Over the last two months two SIDS cases, one in Sydney and another in Canberra were reported in crches. "Care-givers are another group we need to target," says Ms Fitzgerald.

There are certain risk factors that seem to influence the occurrence of SIDS; the irony is that these factors are not reliable in predicting when and if SIDS will take place.

The maternal risk factors are identified as:

• Cigarette smoke during pregnancy
• Mother's age less than 20 years
• Poor prenatal care
• Low weight gain during pregnancy
• Anaemia
• Use of illegal drugs during pregnancy
• History of sexually transmitted diseases or urinary tract infection

For children, exposure to second-hand smoke and lying prone during sleep are the greatest risk factors for SIDS. Community Awareness campaigns over the least ten years have endorsed current research that stresses the importance of lying infants on their backs to sleep. Yet while the "Back to Sleep" campaigns in Britain and the US were credited with dramatically reducing the SIDS death rate in those countries, many SIDS organisers believe these campaigns wrongly influence the public that SIDS is in some way preventable by simply altering the child's environment.

"The last thing we need to do to parents who suffer this tragedy is stigmatise and marginalise them," says Barry Brokaw from the SIDS Alliance Board of Directors in Sacramento, California. "The simple truth is that SIDS can, and does, claim any baby in spite of parents doing everything right."

Because the causes of SIDS are unknown parents will often seek their own explanations for the tragedy and blame themselves, so it is vital that they are reassured that SIDS is nobody's fault. To address the special needs of parents of babies who have dies of SIDS, Australia's National SIDS organisation is directing money into Grief Counselling as part of its overall SIDS strategy.

The three key instructions SIDS Australia gives to parents to reduce the risk of SIDS are:

• Put your baby on its back to sleep
• Make sure your baby's head remains uncovered during sleep
• Keep your baby smokefree, before and after birth

June 29th is Red Nose Day in Australia. Profits from the sale of red noses and badges will go towards funding research into Sudden Infant Death Syndrome.