A new study has said that babies born to mothers who suffered from depression during pregnancy are more likely to experience significant delays in their development as compared to their normal counterparts.
Postnatal depression is known to cause this, but the researchers say antenatal depression can have its own impact.
Writing in the BJOG journal, the researchers said it could mean a third greater chance of cognitive or behavioural problems.
Midwives are trained to spot depression, and report significant problems to GPs.
There is still a stigma attached to depression and mental illness in pregnancy, and sometimes it can help just to acknowledge there is a problem
The study looked at the records of 11,098 women and their children who gave birth in 1991 and 1992.
They assessed the level of depression shown by women during pregnancy, then looked for a relationship between this and any developmental problems in their children.
Women with persistent depression during pregnancy were 50 percent more likely to have children with diagnosed problems.
However, some of that risk comes from the fact that being depressed during pregnancy boosts the chances of postnatal depression, a known risk factor for developmental delay in children.
The scientists worked out, however, that a 34percent rise in risk could be linked independently to antenatal depression, and nothing else.
"The most important finding is that maternal antenatal depression has a negative impact on children's cognitive development, even when postnatal depression has been taken into account," BBC quoted Dr Toity Deave, from the Centre for Child and Adolescent Health at the University of the West of England, as saying.
Professor Philip Steer, the editor of the BJOG journal, said that it was "essential" for doctors and midwives to play an active role in assessing and identifying the condition.