The mean diurnal blood glucose concentration in non-diabetic pregnant women is around 5 mmol/L at 30 weeks of gestation. Diabetic women should be aiming for this level of control, attempting to obtain fasting and preprandial values of between 4 and 6 mmol/L and postprandial values of less than 10 mmol/L. This will be reflected in an HbAlc value within the normal non-diabetic range, certainly <7% and preferably close to 6%. It must not be forgotten that there is also a physiological reduction in glycaemic values observed by around 20 weeks of gestation. This reduction in HbAlc levels is due to the increased haematopoiesis and the presence of unglycated red cells in the circulation in pregnancy. Health professionals and women may frequently be unaware of this pattern and may falsely attribute this physiological shift to an improvement in control.
Home blood glucose measurement is an essential routine aspect of self-management and should be performed 4-6 times/day to recognise the need for insulin dose modification. This dosage adjustment can be performed by the medical team, but the patient should be encouraged and helped to gain the confidence to undertake this herself. Continuous blood glucose profiling may be a useful additional tool to assessing and optimising glycaemic control. HbAlc levels should be measured regularly as this provides an objective assessment of glycaemic control. Target values should be the middle of the normal non-diabetic range.
Hypoglycaemia is an inevitable consequence of achieving strict glycaemic control. All women on insulin should therefore be provided with glucagon 1 mg (Lilly) or GlucaGen (Novo-Nordisk) for use in moderate to severe hypoglycaemia and their relatives should be instructed in its use.