Kate met staff and clients and health professionals at Colham Manor Children's Centre in Hillingdon, west London, in her role as patron of the Maternal Mental Health Alliance (MMHA).
During her tour of the centre, Kate heard how the care provided in Hillingdon is targeted for the needs of the women and their families.
She met women who have been supported by two of the MMHA's member organisations — Home-Start and Birth Companions.
The princess joined a mother and baby group and spoke with mums who have received mental health support to hear about their experiences of the borough's integrated care system.
MMHA is a UK-wide charity and network of more than 100 organisations, working to ensuring women and families affected by perinatal mental problems have access to high-quality comprehensive care and support.
Kate met representatives from agencies working across perinatal services in Hillingdon, including specialist psychiatry staff, midwives, health visitors and social workers, for a round-table discussion convened by the MMHA.
Within the discussion, the group told how the service has developed to meet the needs of the most vulnerable mothers in their community, the impact this has had, and opportunities for further growth.
Earlier this year, Prince William and Kate recorded a special programme on BBC Radio One’s Newsbeat to mark World Mental Health Day.
The royal couple talked to advocates and experts about young people and their mental well-being.
They showed off mental health tools that can provide people with coping skills and resources to ease anxiety and depression.
And earlier this week, the Prince of Wales spoke with England football stars about how sport has bolstered their mental well-being.