A controversial method of "sleep training" in which babies cry themselves to sleep does help babies fall asleep sooner and doesn't appear to have harmful effects. But an alternative technique works almost as well, a new study has found.

A relatively small randomized, controlled trial involving 43 infants between the ages of six months and 16 months tested two techniques to help parents whose babies were having trouble falling asleep and were waking up often in the middle of the night:

Graduated extinction, also known as the Ferber method, where parents allow children to cry for longer and longer periods of time before the parents come in and comfort them, until the child falls asleep.

Bedtime fading, in which the child's bedtime is gradually moved later and later in the hopes the child will be sleepier and fall asleep more easily.

The study was led by Michael Gradisar, an associate professor at Flinders University in Australia and director of the university's Child and Adolescent Sleep Clinic.

It looks like you've got two effective treatments that don't necessarily lead to negative outcomes. - Michael Gradisar, Flinders University

At the start of the study, it took babies an average of about 18 minutes to fall asleep. Both techniques resulted in babies falling asleep faster (13 minutes and 10 minutes faster, respectively) after being put to bed than infants whose parents didn't use one of the techniques and were told to keep doing what they had been doing, such as rocking their children to sleep.

Babies whose parents used the graduated extinction technique also woke up less during the night. The bedtime fading technique had no effect on night waking.

One of the goals of the study, published today in the journal Pediatrics, was to test claims that graduated extinction is stressful for infants and "had the potential for damage," Gradisar told CBC News. For example, a 2012 University of North Texas study reported elevated stress hormone levels in infants treated with the technique.

No long-term stress

Gradisar's study measured levels of the stress hormone cortisol in the saliva of the infants in the morning and in the afternoon, looking for elevated levels that could indicate long-term stress. The measurements could not detect immediate stress during the treatment.

The study did not find elevated levels in the infants who received graduated extinction. Nor did it find significant differences in parental attachment or behavioural problems in those infants 12 months later.

"It looks like you've got two effective treatments that don't necessarily lead to negative outcomes," Gradisar said of the results.

He acknowledged that graduated extinction isn't necessarily an easy technique for parents.

"It is a stressful thing for parents to go through," he said.

However, he noted that his co-author, Kate Jackson, who was delivering the interventions, also found it stressful to take calls from parents in the control group, whose children showed far less improvement.

A similar 2012 study of 326 children with sleep problems at seven months found no evidence that techniques based on allowing babies to cry themselves to sleep had any long-term negative impact on either sleep or behaviour five years later.

The Child and Adolescent Sleep Clinic at Flinders University generally recommends that parents try bedtime fading first. It also recommends that when people try graduated extinction, they set aside a few days when they don't have plans the next day and call in extra support.

Complete recommendations for both techniques are on the clinic's website.