Around 50 babies die from Sudden Infant Death Syndrome every year and finally, we're coming to understand why.
In a world first, University of Adelaide researchers have found a strong link that babies who die from SIDS lack a chemical in their brain (Substance P).
The chemical could make it harder to wake up if they're struggling to breathe.
Researcher Fiona Bright says 'the normal response of an infant is to wake up, to cry, to turn their head and neck out of an unsafe environment of low oxygen'.
The study looked into more than 50 cases from the United States.
Bright is now looking into developing a test which could let parents know if their child is at an increased risk.
SIDS is described as the unexplained death of babies up to a year old.
Sometimes a baby who seems healthy dies during sleep and it can happen even when you do everything right.
Although SIDS is rare, it is one of the most common causes of death in babies between 1 and 12 months of age.
The study also revealed the chemical was significantly influenced in premature babies and also in males.