Diabetes and correlation of foetal abnormality with HBA1c

There is an increased risk of congenital abnormalities . In the CEMACH  study of pre-existing diabetes the overall rate was 4% with a three fold increase in the rates of both neural tube defects and congenital heart disease time of conception and directly correlated with the Hba1c . Women with HbA1c <8% have a risk of approximately 5 % but in those with levels >10 % the risk is as high as 25%. The risk is eliminate if normal HbA1c levels are achieved. The recommendation is that the HbA1c should be <7% and <6.1% in the United Kingdom if safely achievable at the time of conception.

The specific congenital abnormality associated with diabetes is sacral agenesis , but this is very rare. Much more common are congenital heart defects skeletal abnormalities and neural tube defects.

The perinatal and neonatal mortality rates can be increased 5 to 10 fold in babies of mothers with diabetes and these too relate to HbA1c at conception and in early pregnancy . In the CEMACH study of diabetes in pregnancy in the United Kingdom the perinatal mortality rate for both type 1 and type 2 diabetes was about 3 %.