A study conducted by the Centre for Child and Adolescent Health at the University of the West of England indicates that some of the harmful effects on early child development attributed to postpartum depression may be caused partly by antepartum depression, or depression during pregnancy.

"It is widely acknowledged that postnatal (postpartum) depression has a negative impact on child development but this is the first study that has demonstrated that the children of women who experience low mood during pregnancy are also at risk," said Deave.

Deave and colleagues found that persistent depression in the mother during pregnancy increased the odds of developmental delay in the son or daughter by 50 percent. This study, they say, adds to "increasing evidence that the mother’s mood during pregnancy is important" and that any persistent depression during pregnancy has the potential to raise the risk for developmental delay in childhood.