Results of a preliminary study suggest that children exposed to marijuana in the womb may experience sleep disturbances. Researchers conducted sleep studies in 18 three-year-old children with prenatal marijuana exposure and compared them to 20 children not exposed to marijuana. They found that children exposed to marijuana experienced more than two times the number of sleep arousals at night than the comparison group. They also experienced more time awake after each sleep arousal.

Previous studies have shown that marijuana can cause changes in sleep patterns among adult users. Since marijuana affects areas of the brain that regulate sleep, the researchers say it is not a surprise to see that marijuana exposure in the womb may alter development of the same areas in the fetus and thus cause permanent changes in sleep patterns. The most common effects of sleep disturbances in children include problems with attention span, and behavioural and emotional difficulties.

(Archives of Pediatric and Adolescent Medicine, Vol 149, 1995, pp 145-150)