The figures, uncovered by The Herald, show the number of mothers killed by complications linked to pregnancy and delivery doubled in five years. Among them were women who were otherwise very healthy.
Experts who look into each death are still going through cases from 2010 and 2011. They have nine files for 2010 and 20 for 2011 but insist this does not reflect a massive increase in deaths as some mothers who died from other causes, such as car crash victims, are still included in the data.
The Herald asked for the numbers using Freedom of Information legislation after the death of Dr Fiona Agnew, a GP who died in Forth Valley the day after she gave birth to a stillborn daughter last year. Her family described her death as sudden and unexpected.
NHS officials initially refused to reveal the figures and only released the information after an appeal was lodged. Their response reveals that between 2003 and 2009 there were 34 maternal deaths, an average of 4.8 a year. Between 2005 and 2009 the number of tragedies climbed gradually from a low of three to six.
Jackie Baillie, Scottish Labour health spokeswoman, said: "Although the overall numbers are small, behind each of these statistics lies a real human tragedy. At the very least the Government should be publishing these troubling statistics so the NHS can learn lessons from them."
Cases where women have died as a result of pregnancy and childbirth in Scotland have been submitted to a UK-wide study, known as Saving Mothers' Lives, in the past.
Dr Catherine Calderwood, medical adviser for women's health to the Scottish Government, said many different health professionals were asked to comment on each case for this report so the process was time-consuming. However, she admitted the deaths had not been scrutinised fast enough either by this system or in Scotland.
She revealed a new drive to improve the safety of maternity services is being launched this year. A team will also start a more rapid review of cases where women become seriously ill to see if the NHS could have given them better care.
Ms Calderwood said: "It is fair to say there is some evidence there are some avoidable and preventable deaths and that is what this new clinical outcome process is aiming to do – look at the data and come out with lessons."
She also said staff had not always been supported to make changes in response to existing recommendations for improving maternity care, but action would now be taken to turn words into action. Ms Calderwood said: "We want to make sure translating it to the bedside happens in a much more real-time way. That is what is needed because if there is a problem or a trend and you do not find out about it for three years that is not very helpful."
Maureen Treadwell, of the Birth Trauma Association, said probes into maternal deaths had revealed recurring issues with NHS treatment, among them the need for the right medical expert to be in the right place at the right time.
She raised concern that consultant-run maternity departments had been
centralised into "mega units" meaning women were now often further away from specialist care when they went into labour or ran into problems. She also said: "We need less of the blame culture and more willingness to look at the deaths and saying 'we have got to do something about this'."
Emma Currer, national officer for the Royal College of Midwives in Scotland, said there were 58,000 births a year in Scotland and deaths were a rare event. Maternal death figures, she added, include deaths up to a year after delivery and feature post-natal suicides.
A spokeman for Healthcare Improvement Scotland which provided the data said: "The numbers for 2010 and 2011 have not been through the independent classification process that determines those deaths that have a clear connection to maternity – directly or indirectly – and will currently include coincidental deaths (for example, from substance misuse or road traffic accidents) up to one year after childbirth or the end of the pregnancy. We are confident the classification process, once complete, will see the figures for 2010 and 2011 comparable with previous years."
Health boards conduct their own investigation into maternal deaths but there is no agreed structure for these inquiries.