ABSTRACT
The prevalence of pre-existing diabetes in pregnancy in the United Kingdom is about 0.4% (0.27% type 1 and 0.1% type 2). A possible viral component to the aetiology is thought to explain the seasonal incidence (spring and autumn). Women with pre-existing type 1 diabetes are managed using a sliding scale/variable rate insulin infusion. Intravenous infusions of short-acting insulin and dextrose are administered throughout active labour and delivery via separate giving sets. In addition outside pregnancy type 2 diabetes may now be diagnosed using glycosylated haemoglobin threshold of 48 mmol/L (6.5%). As with pre-existing diabetes, close collaboration between obstetricians and physicians is essential. Women should be managed in a specialist multidisciplinary diabetes pregnancy clinic. Carbohydrates with a low glycaemic index (resulting in slower more even release of glucose) are advised (e.g., bran). In a trial, significantly fewer women with gestational diabetes mellitus randomized to a low glycaemic index diet required insulin (29%) than those randomized to a high-fibre diet (59%).
