Using data from the National Longitudinal Study of Youth, which tracks the health of young mothers and their children from birth since 1986, the researchers looked at the impact of maternal depression on children's behavior and injury rates among 1,106 mother and child pairs from 1992 to 1994.

In total, 94 children, all under the age of 6, had sustained injuries, sufficient to require medical attention during the study period. Two-thirds of these injuries had happened at home.

The study, published in the journal Injury Prevention, found children whose mothers scored persistently high marks on the depression scales were more than twice as likely to have been injured as those whose mothers had a low rating.

Children whose mothers had a high depression rating were significantly more likely to have behavioral problems and to "act out." Boys were more at risk of this than girls, the study said.