Washington, D.C. ? More than half of babies in poverty are being raised by mothers who show symptoms of mild to severe depression, potentially creating problems in parenting and in child development, according to a study.

In what was described as the first detailed portrait of its kind, researchers reported that one in nine infants in poverty had a mother with severe depression and that such mothers typically breastfed their children for shorter periods than other mothers who were poor.

“A mom who is too sad to get up in the morning won’t be able to take care of all of her child’s practical needs,” said researcher Olivia Golden, who co-authored the paper with two colleagues at the Washington-based Urban Institute. “If she is not able to take joy in her child, talk baby talk, play with the child — those are features of parenting that brain development research has told us contribute to babies’ and toddlers’ successful development.”