Depression affects one in five women during pregnancy or within two months of having a baby, but less than half will be diagnosed and receive the help they need.
A groundbreaking new study by the University of York will explore how to improve the rates of diagnosis and treatment.
ITV News Tyne Tees correspondent Frances Read reports.
*What is postnatal depression? *
The depressive illness affects around one in ten women, according to statistics.
It starts within 2 months of giving birth, however women suffering stress during pregnancy could experience postnatal depression.
There is an extensive list of symptoms, such as being irritable, feeling anxious, hopeless, not sleeping, losing interest in sex, feeling guilty and unable to cope.
Some women may develop suicidal thoughts. In these circumstances the advice is to see a GP urgently.
Midwives, health visitors and GPs are able to refer cases.
"I fought in Kosovo and Iraq, but still wasn't safe from postnatal depression"
Major Pip Delamere-Wright is one of the British Army's elite commandos and was the first female soldier to win the prestigious green beret. Her job requires immense physical and mental stamina, which she used in both Kosovo and Iraq.
However, when her baby son was born, she struggled with sleep deprivation and postnatal depression. She said at her lowest point, she felt like walking away and leaving her son all together.
Now she is telling her story to encourage other new mothers to have the courage to seek medical help.