A campaign to reduce cot deaths in Britain has helped cut the overall number, but the proportion of babies who die at weekends remains surprisingly high at nearly one-third of the total, researchers said yesterday. Doctors do not understand why more babies die from cot death, or Sudden Infant Death Syndrome (SIDS), at weekends, but the author of a new study said there are suggestions parents give their babies less attention on Saturday evening and Sunday.

The campaign, which advised parents to ensure babies slept on their backs, has helped to reduce cot deaths by 75 per cent from 1,718 in 1986 to 395 in 1998. But weekend deaths, while also falling in absolute terms, rose as a proportion of the total to just over 32 per cent in 1998 from just over 31 per cent in 1986.

?The increased incidence of SIDS at weekends has persisted or even marginally increased despite the overall reduction in incidence following the ?back to sleep? campaign in the early 1990s,? Professor Peter Helms, of the University of Aberdeen in Scotland, said in the study published in the journal Archives of Disease in Childhood.

SIDS is the leading cause of death in babies under a year old in Britain. Most cot deaths occur at two to four months old, and more boys than girls die this way.

The cause of SIDS is unknown but lying the baby down on its stomach, parental smoking, and old mattresses which may harbour toxic bacteria, have been cited as possible reasons. Helms and his team studied the number of cot deaths in Britain from 1986 to 1990 and from 1993 to 1998. They found that the weekend peak was more evident in babies of four months or younger.

?The reason for this can only be speculative and as suggested by others could be due to less parental attention to the needs of their infants on Saturday evenings and Sundays,? Helms added.