Most people think depression is a ''normal'' part of pregnancy and women do not need treatment, according to a survey by the mental health group beyondblue.
The nationwide survey of 733 men and women also found that 57 per cent of people believed women get postnatal depression because they have unrealistic expectations of motherhood. One-quarter thought postnatal depression did not need treatment and would go away on its own.
Beyondblue's deputy chief executive officer, Nicole Highet, said the results were concerning. "If people think that depression is a normal consequence of pregnancy, they're less likely to seek help. This has important implications for the detection and treatment of depression, given that one in 10 women will experience this illness while pregnant.''
Dr Highet, a psychologist, said there was confusion between postnatal depression and the baby blues, where women felt teary and emotional for up to 10 days after giving birth.
The baby blues, which affected up to 80 per cent of women, were triggered by hormonal changes and disappeared quite quickly. But postnatal depression did not disappear on its own and needed treatment, she said. If women did not realise they had the condition, they could miss out on the benefits of early intervention.
The faster you detect it and treat it, the faster the woman recovers. It's also easier to treat mild or moderate depression than when it becomes severe.
''A lot of postnatal depression might be just put down to the normal part of having a baby. [Then] it wouldn't be picked up early, it wouldn't be treated early and it may become more severe,'' she said.
''The faster you detect it and treat it, the faster the woman recovers. It's also easier to treat mild or moderate depression than when it becomes severe.''
Mild and moderate cases responded to psychological treatment but severe cases often required drugs, which was an issue if the woman was pregnant or breastfeeding.
The survey results, released to coincide with a postnatal depression awareness week which began yesterday, did offer some encouragement to beyondblue, which advocates screening all pregnant women and new mothers. More than three-quarters of people agreed that women should be checked for depression both during pregnancy and after birth and 90 per cent agreed that it was a serious condition.
The vast majority (92 per cent) believed women with postnatal depression could be good mothers, but this declined among people aged over 55.
''They tend to be more judgemental,'' Dr Highet said. ''This might exacerbate the problem for women if their mothers or mothers-in-law felt they were not coping.''
One symptom of postnatal depression was low self-esteem, which could be made worse by an older relative's criticism of a new mother.
Beyondblue has been working on national guidelines for postnatal depression. The survey results will be used in an awareness campaign for women and their partners and health workers.
Federal and state governments have committed $85 million to assess pregnant women and new mothers for depression and anxiety and to provide better care and support over the next five years.
Discuss post-natal depression with other Mums in our dedicated Mental Health forum.