Sleeping Through the Night: A Developmental Perspective

This study examines falling asleep and night waking in human infants during the first 8 months of life. All-night time-lapse video recordings were obtained at 3 weeks and 3 months of age; a Sleep Habits Interview was completed at these ages and repeated at 8 months of age by telephone interview. At the 3-week and 3-month ages, self-report measures of maternal psychologic distress, depression, and self-esteem were also obtained. The data are examined from both cross-sectional (age group) and longitudnal (individual) perspectives. Parent-infant interactions at bedtime and during the middle of the night changed significantly with increasing age. At 3 weeks of age, most infants were put into their cribs for the night already asleep. When they awakened in the middle of the night, they were removed from their cribs. By the time they returned to their cribs, they were again asleep. By 3 months of age, infants who were put into the crib awake at bedtime and allowed to fall asleep on their own were more likely to return to sleep on their own after awakenings later in the night. In contrast, infants who were put into the crib already asleep at the beginning of the night were significantly more likely to be removed from the crib following a subsequent nighttime awakening. Thus, the pattern of bedtime sleep onset was related to sleep onset following an awakening in the middle of the night. This association was present at 8 months as well. Infants who used sleep aids were more likely to be put into their cribs awake at bedtime and were also more likely to return to sleep on their own after a nighttime awakening at both 3 and 8 months of age. At 8 months of age, 7 of the 21 infants were identified by their mothers as problem sleepers. All were male infants who were still put into their cribs asleep at the beginning of the night. These individuals could not be predicted from 3-week or 3-month observations of video-recorded sleep-wake state organization or mother-infant interaction. The authors speculate about the interplay between sleep-wake state regulation, nighttime interactions, problem sleep, temperament and maternal factors such as depression, self-esteem, and stress.