Babies born to women with diabetes are five times more likely to die at birth than those born to mothers without the condition, say doctors.
A study carried out by doctors in the north-west of England also found that diabetic women were two and a half times more likely to have babies with birth defects.
The doctors compared these findings with figures from Sweden. They found that babies born to women with diabetes in Swden were much less likely to either die or have birth defects. A spokeswoman for the charity Diabetes UK said the risks can be reduced with careful planning.
"While women with diabetes and their unborn children are at a greater risk of developing complications during pregnancy compared to women who do not have diabetes, studies have proven that these risks can be reduced by keeping blood glucose levels in good control. "With adequate medical support and careful planning of the pregnancy, women with diabetes will further minimise the risks to their pregnancy."