The research suggests how parents, infants and toddlers all can get a better night's sleep by making bedtime arrangements as consistent as possible.
Marie Hayes, professor of psychology, and Michio Fukumizu, a pediatric neurologist from Tokyo, Japan, and visiting scholar in the UMaine psychology department, with two Japanese co-researchers have identified several factors in an infant's first few months of life that can affect how they sleep and how often they awaken in distress during the night.
The results of their research were published in an article, "Sleep-Related Nighttime Crying (Yonaki) in Japan: A Community-Based Study," in the January issue of the journal Pediatrics, with colleagues and co-authors Makiko Kaga, M.D., director of the National Institute of Mental Health, National Center of Neurology and Psychiatry in Japan, and Jun Kohyama, M.D., associate director of Tokyo Kita Shakai Hoken Hospital.
The study involved interviews with the parents of 500 infants, toddlers and children at a well-infant clinic in Tokyo. It is customary in Japan for parents to bring infants and toddlers into their sleeping quarters typically a mattress on the floor (tatami) to nurse and fall asleep. Later, most infants stay with the parents, a practice termed "co-sleeping," which makes the child more accessible to the parent during the night. For a small percentage of infants, sleep occurs in a separate crib-like bed away from the parents but in the same room.
The study's findings suggest a critical factor contributing to night-waking is not as much co-sleeping or separate sleeping arrangements, but rather changes in where the infant sleeps during the night and during naps.