Gestational diabetes: aetiology and management

It is well known that raised glucose levels in women with established diabetes increase both morbidity and mortality among their offspring due mainly to an increased incidence of congenital abnormalities and excessive fetal growth in the third trimester. Whether milder elevations of maternal glucose are clinically relevant in pregnancy has been controversial. However, emerging evidence points to a linear increase in fetal risk as maternal glucose concentrations rise. Much of this morbidity can be prevented with aggressive treatment of hyperglycaemia, often with insulin. Furthermore, transient glucose intolerance in pregnancy has major implications for the women affected, since it confers a risk of type 2 diabetes in later life which exceeds 50%. It is therefore now established that gestational diabetes mellitus is of considerable clinical relevance. Obstetric units should establish clear policies to ensure that those at risk are reliably identified, appropriately treated during pregnancy and then equipped to make the necessary lifestyle changes to try and prevent them developing diabetes in later life.