Breastfeeding might help to protect babies against cot death, according to new research.

Scientists writing in the medical journal Archives of Disease in Childhood published today have found that the babies of mothers who breastfeed are slightly but significantly less likely to die of sudden infant death syndrome (Sids or cot death) than babies who are bottlefed.

The research was carried out in Norway, Sweden and Denmark, headed by Bernt Alm at Queen Silvia children's hospital in Gothenburg.

The team surveyed the parents of 244 babies who had died unexplained deaths at tributed to Sids and the parents of 869 babies who were alive and well.

During the study period, which ran from 1992 to 1995, breastfeeding dropped among the Sids babies from just under 56% to just over 47%. Breastfeeding among the healthy babies was more common to begin with and also rose during the study period, from 56% to almost 74%.

After taking into consideration factors likely to skew the results, such as the mother's smoking habit, income, sleeping position and the baby's age, the researchers calculated that babies breastfed for less than eight weeks had between three and five times the risk of dying from cot death of babies breastfed for four months or more.