[Nihon kōshū eisei zasshi] Japanese journal of public health
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Nihon Koshu Eisei Zasshi · Jul 2007
[Sleep of 4-month-old infants: bedtime, night waking and sleep problems].
Recently, Japanese infant's bedtime has become late and it is reported that this might have a bad influence on infant's growth. The purpose of the present study was to investigate the actual situation and interrelationships between night waking and other sleep problems in Japanese 4-month -old infant. ⋯ Late bedtime and high proportion of night waking in 4-month-old infants were found to be characteristic in Fukuoka city. There is a possibility that night waking reflects delayed development of circadian rhythms.