Pre-Natal Alcohol Exposure Predicts Poor Sleep in Children
Science Daily reports that the study indicates that children exposed prenatally to alcohol were 2.5 times more likely to have a short sleep duration of 7.7 hours or less and 3.6 times more likely to have a low sleep efficiency of 77.2 percent or less across all nights, independent of body size at birth and current maternal alcohol use.
Smaller body size at birth was also associated with poorer sleep and a higher risk of clinically significant sleep disturbances among children born at term. Lower weight and shorter length at birth were associated with lower sleep efficiency, and a lower ponderal index (an indicator of fetal growth status) was associated with sleep disturbances. Children with short sleep duration were more likely to have born via Caesarean section than children who slept longer (23.1 percent versus 8.4 percent).
Principal investigator Katri Räikkönen, PhD, in the department of psychology at the University of Helsinki, Finland, said that even low levels of weekly prenatal exposure to alcohol have adverse effects on sleep quality and quantity during childhood.
"The results were in accordance with the fetal origins of health and disease hypothesis and the many studies that have shown that adverse fetal environment may have lifelong influences on health and behavior," said Räikkönen.
"However, this is among the few studies that have reported associations between birth variables and sleep quality and quantity among an otherwise healthy population of children."
The study gathered data from 289 children born at term (from 37 to 42 weeks of gestation) between March and November 1988. Sleep duration and sleep efficiency (actual sleep time divided by the time in bed) were measured objectively by actigraphy at 8 years of age for an average of 7.1 days. Parents completed the Sleep Disturbance Scale for Children to report sleep problems and sleep disorder symptoms such as bedtime resistance and sleep disordered breathing.
Results show that the odds for low sleep efficiency increased by 70 percent for every standard deviation decrease in weight at birth and by more than 200 percent for every decrease in length. For every standard deviation decrease in ponderal index at birth, the risk of parent-reported sleep disorders increased by 40 percent.
The authors conclude that small body size at birth may be a marker of disturbances in the fetal environment and that it is associated with prematurity, growth retardation, prenatal alcohol exposure, and poorer sleep quality in children and adults. Among children born healthy and at full term, a linear relationship exists between smaller body size at birth and poorer sleep quality at 8 years of age.