Washington, Aug 2 (ANI): Pregnant mothers who indulge in boozing can disrupt their children's sleep for years afterwards, researchers say.

A study in the Aug.1 issue of the journal sleep found that alcohol consumption during pregnancy and small body size at birth predict poorer sleep and higher risk of sleep disturbances in 8-year-old children born at term.

Results indicate 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 also was associated with poorer sleep and with a higher risk for clinically significant sleep disturbances among children born at term. More specifically, 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 the presence of sleep disturbances.

Additionally, children with short sleep duration were more likely to have been born via Caesarean section than were children sleeping longer (23.1 percent versus 8.4 percent respectively).

According to principal investigator Katri Reikkenen, PhD, in the department of psychology at the University of Helsinki, Finland, even low levels of weekly prenatal exposure to alcohol have adverse effects on sleep quantity and quality 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 Reikkenen.

"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 expert added.

The epidemiologic cohort study obtained data from 289 children born at term (from 37 to 42 weeks of gestation) between March and November 1998.