A recently published study looked at the sleep patterns in babies and adults when co-sleeping, when the child sleeps in the same room or bed as the parent(s), or solitary sleeping, when the child sleeps in a separate room from the parent(s). Solitary sleep is more common in the US and other Western cultures, whereas co-sleeping is more common in non-Western cultures. This study was conducted with babies under the age of two and their mothers in central Pennsylvania.
When an infant was 1 month old, the majority of parent(s) co-slept with their babies, either in their bed or in the same room (72%). Interestingly, this percentage decreased drastically over the next 11 months to 17% for 12-month-old infants. By 6 months old, the majority of infants were solitary sleepers.
Mothers who co-slept with their infants beyond 6 months were more likely to feel criticized about their choice of sleeping arrangements and consistently reported higher levels of depressive symptoms. This study looked at four different categories for the mothers – criticism, depression, anxiety, and worry about infant sleep. All of these were more prevalent in mother’s who co-slept with their infant beyond 6 months. It is unclear whether co-sleeping led to more feelings of criticism, depression, anxiety and worry. Or vice versa, that mothers who experienced more feelings of criticism, anxiety, depression, and worry tended to co-sleep. Bottom line is that the choices that parents make about their child’s sleeping arrangements not only reflect on the infant but on the parents as well.
These results might be helpful if you are considering whether or not to co-sleep with your infant beyond 6-months. This post from Allice Callahan, PhD (Science of Mom) may also be helpful.