Infant co-sleeping patterns and maternal sleep quality among Hadza hunter-gatherers

Despite widespread interest in maternal-infant co-sleeping, few quantified data on sleep patterns outside of the cultural west exist. Here, we provide the first report on co-sleeping behavior and maternal sleep quality among habitually co-sleeping hunter-gatherers.

Data were collected among the Hadza of Tanzania who live in domiciles constructed of grass huts with no access to synthetic lighting or climate controlled sleeping environments. Using interview data, we recorded baseline ethnographic data on co-sleeping. Using actigraph data, we tested whether sleep quality, sleep-wake activity, and/or sleep duration differs among breastfeeding women, non-breastfeeding women, and men.

CamNtech Motionwatch 8 actigraphs were used to collect 1 minute, epoch-by-epoch data on a sample of 33 adults. Functional linear modeling (FLM) was used to characterize sleep-wake patterns and a linear mixed-effects model was used to assess factors that drive sleep duration and quality.

The FLM suggests that breastfeeding mothers were early risers and had reduced day-time activity. Additionally, total number of co-sleepers, not breastfeeding, was associated with less sleep duration and quality, suggesting that greater number of co-sleepers may be a primary driver of poorer sleep.

The current study makes important contributions to the cross-cultural literature on sleep and augments our understanding of maternal-infant co-sleeping. The majority of Hadza participants co-sleep with at least one other individual and the majority of married couples sleep with their spouse and their children on the same sleeping surface. Our preliminary sleep quality data suggest that breastfeeding does not negatively impact maternal sleep quality.