An increasing workload for health visitors has resulted in less contact between GP and patient, which is vital for diagnosing depression, said the report.
The study involved interviews with 19 GPs and 14 health visitors in nine PCTs in Bristol, London and Manchester.
GPs felt that knowing the patient was important in making the diagnosis.
However, health visitors were less likely to keep the GP informed about the patient during the pregnancy and were reluctant to refer those vulnerable to postnatal depression to GPs, said respondents.
The report said that health visitors were increasingly distant from GPs and did not offer routine follow-up after birth.
Dr Cheryll Adams, acting lead professional officer of the Community Practitioners' and Health Visitors' Association, agreed that the situation was worrying and GPs and health visitors needed regular contact.
'Because of organisational changes and financial cut backs, health visitors can be working with up to 30 GPs. I am very worried about services for postnatal depression,' she said.
Dr Adams wanted to see all health professionals asking basic questions that would help to diagnose postnatal depression.
'The new standards from NICE need to be implemented,' she added.
Current NICE guidelines recommend establishing a perinatal service to link maternal, mental health and community services.
BJGP 2008; 58: 169-76