New mothers with postnatal depression experience poor care and are usually given pills when they should have therapy, a mental health charity says.
One in six new mothers are believed to experience some mental distress
Mind's snapshot survey of 148 women in England found one in 10 had to wait over a year for treatment.
And four-fifths of those admitted to psychiatric wards were separated from their babies.
The government's mental health tsar said it was working on improving access to effective care and treatment.
Mind said one in six women is known to be affected by mental distress during pregnancy or following childbirth, and 25% of all maternal deaths are linked to mental health problems.
Its survey found 75% of the women were given medication, with the remainder offered counselling.
Over two-thirds had to wait more than a month for treatment.
Ninety per cent of the women said the problems they experienced in accessing care were due to a lack of understanding by health professionals
The situation was worst in the north of England.
The charity said its key concerns were a lack of mother and baby units - with just 17 in England and Wales, two in Scotland and none in Northern Ireland - poor treatment choice, and lack of training for health professionals leading to diagnosis problems.
A spokeswoman added: "Although postnatal depression is publicly recognised, many people, including health professionals, don't recognise it quickly enough as being more than just 'baby blues'.
"Some women reported waits of up to two years for cognitive behavioural therapy (CBT).
"This is particularly crucial for mothers, as recent research has suggested that mothers using antidepressants during pregnancy doubles the risk of stillborn births and low birth weights."
Marjorie Wallace, chief executive of the mental health charity Sane, said: " Whilst the evidence linking damage to the unborn baby must be taken very seriously, it is also important to take into account the risks of the illness itself - those with depression can often lose appetite, neglect their physical health and, at worst, become suicidal.
"There is also evidence that babies of mothers taking antidepressants may experience withdrawal symptoms after birth.
"Although all drugs should be avoided during pregnancy, such is the shortage of psychological therapists that GPs often have few alternatives.
"It is urgent that the government increase people's access to psychological treatments, to minimise the need for medication."
Professor Louis Appleby, the government's national clinical director for mental health, said the government recognised the need to improve access to effective care and treatment for new mothers affected by depression.
He said two new pilot centres in Doncaster and Newham would improve women's access to therapy.
Professor Appleby added: "To address varying levels of care, we have asked the National Institute for Health and Clinical Excellence to produce guidance for the NHS on this very area. This is expected early next year."
But shadow health minister Tim Loughton said: "The findings of today's report flies in the face of the government's recent announcement that they would make talking therapies more widely available.
"It is completely unacceptable that 10% of these women who present to their doctor with mental health problems have to wait over a year to receive treatment."