How often do families tell us they are concerned because their infant of 6 months of age or older is still not sleeping through the night? Why is this important? Is sleep associated with the child’s development? Pennestri et al. (0.1542/peds.2017-4330) decided to answer these questions in a new study of 388 infants in a longitudinal cohort whose sleep habits and development were assessed at 6 and 12 months of age based on maternal reports and developmental testing. You may be surprised to learn that using a definition of 6 hours of sleep as “uninterrupted,” 27.9% of 6 and 12-month-olds were still not sleeping through the night, and if you make 8 hours the definition of “uninterrupted sleep,” then the percentage not sleeping increases to 57%. What does that mean for the psychomotor and mental development of these children who were not sleeping through the night? Nothing—in that developmental testing did not reveal any differences between those who slept soundly and those who did not. In addition, the authors noted that maternal mood was also not affected by shorter or longer periods of uninterrupted sleep. The only difference noted was that infants who slept through the night had a statistically significant lower rate of breastfeeding.
So what does this mean? Should we stop helping families try to find ways to get their infants to sleep through the night? To answer that question, we asked sleep specialists Drs. Jodi Mindell and Melisa Moore to provide a commentary about the implications of this study and its findings (10.1542/peds.2018-2589). The authors note that there are a number of studies that show opposite findings (i.e. where sleep duration does seem to be associated with development) but also comment on the differences in a number of factors in each of these studies that might be the reason for differences found. In addition, they speculate on why duration of uninterrupted sleep may or may not make a long-term difference, but still might be playing a role in short term day to day differences in behavior and mood for an infant and for the parent who is called up in the middle of the night to feed or sooth that infant. You won’t fall asleep reading either the study or commentary, so link to both and learn more.