If she has access to medical journals:
The Lancet 2006; 367:314-319
Major epidemiological changes in sudden infant death syndrome: a 20-year population-based study in the UK
but you need to have subscription access through a library / the PCT.
You need to be statistically literate to get the most out of the article but essentially it says:
The number of SIDS deaths in both cot-sleeping and bed-sharing babies has fallen.
The number of SIDS deaths in cot-sleeping babies has fallen faster than the number of SIDS deaths in bed-sharing babies.
The number and proportion of SIDS deaths in sofa-sharing babies has risen.
Sleeping with a baby on a sofa is not a safe option.
Most SIDS is now in deprived families.
Most SIDS is in families where the mother smokes.
Tobacco smoke is thought to be part of the causal mechanism for SIDS. 80-90% of SIDS mothers smoked in pregnancy, far more than in the general population of mothers with a similarly deprived socio-economic background.
A higher proportion of SIDS cases are in pre-term infants ? 1/3 of SIDS infants are pre-term, compared with just 5% of infants in the population.
Breastfeeding is rare in the mothers of SIDS infants.