Sleep behavior of pregnant women using sleep log.

Sleep log study, which was designed to study sleep characteristics by questionnaire, was performed on 172 pregnant women about the relationship between their pregnancy and their night sleep. Sleep behavior by sleep log revealed that they woke more frequently during the course of their pregnancy and that their total sleep time decreased gradually toward the end of their pregnancy. According to their subjective evaluations, these shortages of night sleep could not be made up with the morning naps in the multiparas as was the case of the primiparas. These changes in sleep characteristics have been studied from biological, psychological and social factors view points.