A University of Adelaide researcher has announced new national guidelines recommending that women at risk of early preterm birth use magnesium sulphate to protect their babies from cerebral palsy.

Professor Caroline Crowther from the University's Discipline of Obstetrics and Gynaecology and the Robinson Institute says the clinical practice guidelines are based on overwhelming evidence over the past 14 years that magnesium sulphate is effective in protecting the fetus.

"Five trials, including one funded by the National Health and Medical Research Council, confirm this finding," Professor Crowther says.

The clinical guidelines were announced by the Royal Australian and New Zealand College of Obstetricians and Gynaecologists at their annual Scientific Meeting in Adelaide yesterday.

More than 600 children in Australia and more than 120 children in New Zealand are diagnosed with cerebral palsy each year - over a third of which are related to preterm birth.

"The cost to the Australian community of cerebral palsy is nearly $4 billion per annum," Professor Crowther says. "At present there is no cure for this neurological condition, which results in substantial disabilities."

Cerebral palsy affects one in 500 newborn babies overall and one in 10 very premature babies (less than 30 weeks' gestation). Cerebral palsy and cognitive dysfunction are the most frequent occurring neurologic impairment associated with preterm birth.

Magnesium sulphate therapy involves giving doses of magnesium sulphate to pregnant women via injection within 24 hours of birth.

The exact mechanism of magnesium sulphate in protecting the developing brain is not certain. However, magnesium is vital for normal cell function, may protect against destructive molecules that can harm cells, and in some circumstances improves blood flow.

Side effects of the treatment include flushing, sweating, nausea, vomiting, headaches and palpitations. However, researchers have found no increase in major complications in mothers due to magnesium therapy.

Professor Crowther is Director of the University's Australian Research Centre for Health of Women and Babies, based at the Women's and Children's Hospital.

The guidelines apply to health professionals, pregnant women and for policy makers.

Professor Crowther says it will be important to monitor the antenatal use of magnesium sulphate for neuroprotection of the fetus through a national audit and to link data to national childhood cerebral palsy registers.