A judge says an Edmonton foster mother did nothing that contributed to the death of a baby in her care four years ago.

Four-month-old Delonna Sullivan was found unresponsive in a bassinet on April 11, 2011, six days after social workers placed her in the foster home. 

An autopsy found the infant was healthy and the cause of her death was listed as unexplained. 

Provincial court Judge Steven Bilodeau made no recommendations in his fatality inquiry report. 

He says the baby had been sleeping in a safe manner and was being properly supervised. 

The foster mother testified she had checked on the baby several times and was listening on a monitor. 

"In conclusion, this otherwise healthy baby died for an unexplained reason as have other babies all over the world for many, many years," wrote the judge. 

"It is a medical mystery why this happens. She happened to be in the good care of a foster parent at the time this occurred." 

Over the last nine years in Alberta, 166 of 1,048 deaths of children under the age of one have been unexplained or classified as sudden infant death syndrome or sudden unexplained death in infancy, said the report. 

Jamie Sullivan went to court a few months after the death of her daughter and convinced a judge to lift an automatic publication ban on the child's identity. The mother argued she wanted the world to know about Delonna's death. 

The Alberta government has since made changes that allow the publication of names and photos of children who have died in government care, although families can apply to block publication.