Association of fetal eye movement density with sleeping and developmental problems in 1.5-year-old infants

Abstract Eye movement density (EMD) is an evaluation index of rapid eye movements observed during sleep. This study aimed to investigate the association of fetal EMD with sleeping and developmental problems in infancy. We observed 60 normal singleton pregnancies (gestational age 28–37 weeks) using ultrasonography for 1 h. Fetal eye movements were counted, and EMD was calculated. Participants answered questionnaires regarding their child’s sleep and development 1.5 years after their delivery. The outcomes of an infant’s sleep were night awakening (yes or no), bedtime (before or after 22:00), and nighttime sleep duration (