Not sleeping soundly in early infancy is not bad

This study sought to determine whether not sleeping soundly in early infancy predicted poor development. This complemented earlier studies of children aged 12 months or older.

Sleep/wake patterns of 35 Japanese infants (23 males) with a gestational age of 37< weeks were recorded at home using actigraphy. Families were registered with a laboratory-based database for infant research. Follow-up recordings were conducted at 3, 4, 6, 12, and 24 months. Crawling was rated by mothers at 12 months and used to create regular and irregular crawling groups. Temperament was scaled using the Japanese Infant Behaviour Questionnaire-Revised Questionnaire and the Japanese Early Childhood Behaviour Questionnaire.

At 4 months, infants with regular crawling style had shorter night-time sleep than infants with irregular crawling style. However, at 12 months, the former had longer motionless sleep at night compared to the latter. Before 6 months, infants with regular crawling style showed lower sleep efficiency, especially during the day, compared to those with irregular crawling style. In addition, the amount of night-time active sleep at 3 and 4 months were positively correlated with day-time activity, but not at 6 months.

Short fragmental sleep in early infancy did not always predict poor development.