Pregnant women with the kind of diabetes usually triggered by obesity have a five times greater risk of giving birth to a stillborn baby, new research has shown.

The babies of women with type 2 diabetes, as it is known, are also nearly three times more likely to die within the first four weeks of life and are twice as likely as other babies to suffer from major abnormalities such as heart conditions.

The findings, in a report today by the Confidential Enquiry into Maternal and Child Health (CEMACH), which is run by six medical royal colleges, are a particular cause for concern because the number of people with type 2 diabetes is rapidly rising, fuelled by the obesity epidemic.

In the past it was thought that only type 1 diabetes, which means a lifetime on insulin, was a problem in pregnancy. But the biggest study to date has found the risks are just as high in type 2, which is often triggered by obesity. The World Health Organisation warned last week that deaths from this type of diabetes in the UK are likely to rise from 33,000 to 41,000 by 2015.

Type 2 diabetes used to be known as "late onset diabetes", but it is now affecting younger people and even children. CEMACH says out of 2,536 babies born to women with type 2 diabetes between March 1 2002 and February 28 2003, there were 63 stillbirths and a further 22 who died before they were four weeks old.