The report examined 124 deaths of women who died in pregnancy or up to six weeks afterwards between 2013 and 2015 and found that, if they had received better quality care, 41% may have been prevented.

Researchers from the University of Oxford have urged pregnant women not to stop taking medication without expert medical advice. Two thirds of the deaths examined by the report involved women with pre-existing physical or mental health issues.

There were nine deaths within the study of women with epilepsy, seven of which may have been prevented if the standard of their care had been higher, the report said. A number of women who died had stopped taking their medication in the early stages of pregnancy.

Professor Marian Knight, who led the research, told the Press Association:

"I cannot over-emphasise to women with known health conditions the importance of seeking specialist advice before they stop or change their medicines in early pregnancy.

"GPs may not always have the expertise to give this advice and it is best to discuss with someone who has experience of managing your specific condition, such as your epilepsy specialist, psychiatrist or physician trained in pregnancy medicine.”

Maria Panteli, partner in the clinical negligence department, at Leigh Day, said:

“It is tragic to read that two in five deaths among pregnant mothers who died in pregnancy or shortly afterwards could be prevented with better care. I have acted in a number of such cases and, what should be a wonderful and happy time for the family, becomes associated with the devastating impact of the death of the mother.

“It is crucial that pregnant women who are at a higher risk or have pre-existing physical or mental health issues are provided with specific specialist care and that this is identified and put in place at the beginning of their pregnancy.

“Many women may not be aware of the potential impact that their pre-existing health condition may have on them or their baby in order to seek such advice themselves. It is therefore vital that doctors, nurses and midwives are aware of this and, if they do not have the expertise or experience to give this advice, to discuss or refer the woman to a specialist. For example, this may be a psychiatrist, epilepsy specialist, diabetic physician or a physician trained in pregnancy medicine."