Research in US and UK sleep laboratories has demonstrated that a close behavioral and physiological relationship exists between mother-infant co-sleeping pairs which may protect infants against SIDS. However, in interview studies we have found that co-sleeping infants in the North Tees area of England are usually brought into bed with both parents, not just the mother. In this paper we present the initial results of an in-home observation study contrasting what happens to infants sleeping with both parents compared to sleeping with the mother only.

Participants were recruited through midwives, health visitors, baby clinics, and local media reports. Using low-light video cameras and infra-red lights we obtained all-night videos of dyadic (mother-infant) and triadic (mother-father-infant) co-sleeping parents and babies. Videos were coded using a behavioral taxonomy developed during our pilot study which allows us to quantify data on parent-infant sleeping positions, proximity, orientation, sleep state, and frequency and duration of interactions and interventions. Results presented are based on 128 hours of video-taped observations comparing 8 infants sleeping with their mothers only, and with both parents.

On both triadic and dyadic sleeping nights infants spent the majority of the night oriented towards the mother, regardless of the proximity or position of the father. Infants were also commonly observed in closer proximity to the mother than the father, and on triadic nights fathers were found to orient themselves away from the mother-infant pair. Mothers responded both more rapidly, and more frequently, to infants than did fathers. Differences observed between mother-infant interactions on the triadic and dyadic co-sleeping nights were minimal. From these preliminary data we conclude that the presence of the father in the bed has a negligible influence on the night-time relationship which exists between co-sleeping mothers and infants.

We also examined the video tapes for indications that sleeping with both parents may carry more risks for the infant than sleeping with the mother alone. All infants slept between both parents on triadic sleeping nights, and all were placed in a supine position. Using interval sampling we coded the position of bedding, pillows and parents relative to the infant’s body, head and face in both co-sleeping situations. Quantification of the frequency of potential infant-risk events (smothering, overheating, rebreathing CO₂) indicates that infants were not at increased risk when sleeping between both parents versus sleeping with the mother only. Further research will involve the integration of physiological variables.

Funded by Foundation for the Study of Infant Deaths, Nuffield Foundation & University of Durham.