Samantha Evers' son Dominic was five-months-old when she was diagnosed with post natal depression, despite the symptoms showing up in her pregnancy.
"No-one picked it up until my husband picked it up. He had depression when he was younger... And he saw signs in me and forced me to go to the doctor," she said.
There is concern more woman are falling through the cracks, with calls for midwives to be better trained to pick up on signs of depression and anxiety in both new mothers, and expectant mothers.
The Maternal Care Action Group is also pushing for more funding for support services after its research found gaps in midwives' knowledge and practice.
A survey has found 63 per cent of women have reported symptoms of depression during pregnancy, but more than two-thirds were not diagnosed until after the baby was born.
Researchers say the delay could be put down in part to the ability of midwives to identify the warning signs.
Kristina Paterson of the Maternal Care Action Group said it wasn't that midwives did not want to help mothers, it was that the knowledge wasn't there.
Nimsha Waller of AUT Department of Midwifery said mental health was already adequately covered during training, but there needed to be better access to support services.
"It's just trying to get into those services that could be a challenge and thats where more work needs to be done," she said.
The Maternal Care Action Group will be bringing a petition to parliament, calling for more funding for primary care services for women with both antenatal and postnatal depression and better resourcing of midwives through training.