Gestational diabetes: a challenge for the future.

It is well established that pregnancy is associated with temporary changes in maternal metabolism which include a decrease in maternal insulin sensitivity to values similar to those associated with Type 2 diabetes. Fasting glucose concentrations fall throughout pregnancy, postprandial values rise. The maintenance of glucose tolerance in pregnancy requires a two- to three-fold increase in postprandial maternal insulin secretion. Glucose intolerance develops in women unable to compensate for the metabolic changes incurred by pregnancy. Increasing maternal hyperglycaemia is associated with increasing pregnancy morbidity and an increased likelihood of subsequent diabetes in the mother. In addition, maternal hyperglycaemia has a direct effect on the development of the fetal pancreas and is associated with an increased susceptibility to future diabetes in the infant, an effect which is independent of genetic factors. Gestational diabetes mellitus (GDM) is defined as glucose intolerance first recognized in pregnancy, and by definition includes a small number of women with previously unrecognized diabetes or impaired glucose tolerance (IGT). Figures on the prevalence of GDM vary between maternity units, depending on screening methods and the ethnic distribution of the populations. However, in a comprehensive study of a multi-ethnic antenatal population in inner London, UK it was found that only 2% of pregnant women develop significant glucose intolerance. Obstetricians and physicians debate the importance of identifying this 2% of women. The lack of agreed criteria for diagnosing gestational diabetes and the questionable obstetric benefits of treating all women with mild disturbances of glucose tolerance in pregnancy has resulted in few UK centres undertaking universal screening for GDM.(ABSTRACT TRUNCATED AT 250 WORDS)