The study found that the EPDS method, recommended by NICE in its 2007 guidance on postnatal mental health, missed 65 per cent of cases of postnatal depression.
For the research, 147 pregnant women were randomly selected from two general practices in south London.
Three months after giving birth, the women were assessed using the EPDS - a 10-item self-report questionnaire - and face-to-face interviews.
Although 34 women were diagnosed with postnatal depression using the interview method, just 12 were detected using EPDS. This suggests that EPDS has a sensitivity of just 35 per cent.
Dr Sarah Jarvis, RCGP spokeswoman for women's health, said: ‘It can be difficult to diagnose postnatal depression using the EPDS method as patients tend to give you the answers that they think you will want to hear and hide their problems.
‘A combination of interviewing and the EPDS is the best method for detecting postnatal depression.'
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