Washington, Aug 17 - More than a third of pictures in women's magazines depict babies in unsafe sleeping positions, possibly heightening the risk of sudden infant death syndrome (SIDS), says a new study.

SIDS is the sudden and unexpected death of an apparently healthy infant during sleep.

The study led by Rachel Moon, a paediatrician and Brandi Joyner at Children's National Medical Centre (CNMC), analysed pictures of sleeping infants in 24 magazines with wide circulation among 20 to 40-year-old women.

The authors evaluated pictures for sleep positions, including whether or not the baby was placed on its side or stomach rather than on its back, as well as hazards in infant sleeping environments, including soft bedding.