Methods The study comprised 112 randomly selected, apparently healthy infants from the community setting (48 boys, 64 girls) who were singletons born in St Petersburg in 2007, at term and with normal weight. Information about major infant, maternal and demographic characteristics was collected from available medical documents, as well as from maternal interviews. The mothers were requested to answer whether the baby was a solitary sleeper or shared the bed with the parent(s), and to fill in the questionnaire concerning the infant’s behavioural features during sleep.

Results Of 112 infants, 83 (74%) were solitary sleepers, whereas 29 (26%) co-slept with their parent(s). No statistically significant difference was found for major infant, parental and demographic characteristics between the two groups. Co-sleeping babies had significantly higher values (more problems) on sleep duration and night wakening scores. It was more common with them to sleep too little, wake more than twice during the night, and less often return to sleep without help after waking. Significantly higher values were also found on sleep disordered breathing and parasomnia scores in co-sleeping babies. Noisy breathing during sleep was more common in co-sleeping infants. These associations remained significant after adjustment was made for major potential confounders.

Conclusion Co-sleeping with parent(s) in early infancy is associated with maternal reports of more disturbed infant sleep during night time.