The year after a baby is born is an important time in the life of any woman, and an essential period in the social and emotional development of a child. A significant number of women suffer from postnatal depression, however, only a small proportion of sufferers are diagnosed, and fewer are treated appropriately. Inadequate treatment has a detrimental effect on mothers and their families, and may lead to long-term problems in their children. Mental health problems, including suicide, are a leading cause of maternal death. Women who die due to mental illness in the postnatal period often have complicated social and medical problems. GPs are in an ideal position to detect and diagnose postnatal depression, initiate treatment and ensure referral to specialist perinatal mental health services when needed. GPs should be aware of red flag signs for postnatal mental health problems, and be able to coordinate between different services to detect and support women at high risk of harm.