Prenatal and early postnatal measures of brain development and childhood sleep patterns

Background Brain development underlies maturation of sleep patterns throughout childhood. Intrauterine head growth - marker of early neurodevelopment - has not been associated with childhood sleep characteristics. We explored associations between ultrasonographic measures of prenatal and early postnatal neurodevelopment and childhood sleep. Methods A total of 6,808 children from a population-based birth cohort (Generation R) were included. Head circumference (HC) and lateral ventricles size were assessed with mid- and late-pregnancy fetal ultrasounds, and with cranial ultrasound 3-20 weeks postnatally. Mothers reported children's sleep duration at 2 and 3 years, and sleep problems at 1.5, 3, and 6 years. Results Larger ventricular size, but not HC, was related to longer sleep duration at 3 years (β=0.06 h, 95% confidence interval (CI): 0.02; 0.10 in late-pregnancy and β=0.11 h, 95% CI: 0.02; 0.20 in early infancy, mid-pregnancy parameters were unrelated to sleep duration). Larger HC in mid-pregnancy was associated with a reduced risk for being a "problematic sleeper" up to the age of 6 years (odds ratio (OR): 0.94, 95% CI: 0.89; 0.99). Consistently, children with larger HC in early infancy were less likely to be "problematic sleepers" at 3 and 6 years. Conclusions This study shows that variations in fetal and neonatal brain size may underlie behavioral expression of sleep in childhood. Albeit small effect estimates, these associations provide evidence for neurodevelopmental origins of sleep.