Screening for gestational diabetes: The effect of varying blood glucose definitions in the prediction of adverse maternal and infant health outcomes

Abstract

Background: Impaired glucose tolerance in pregnancy and gestational diabetes are associated with increased maternal and fetal risks. There is considerable uncertainty in the literature relating to the merits of screening for gestational diabetes and impaired glucose tolerance, and variable definitions in the cut-off values to be used. Aims: To assess different levels of glucose intolerance in predicting adverse pregnancy outcomes. Methods: Retrospective cohort study involving screening pregnant women with a 50-g oral glucose load, followed by a formal 75-g oral glucose tolerance test for women who screened positive (defined as a plasma glucose level ≥ 7.8 mmol/L). Plasma glucose results were correlated with pregnancy and birth outcomes, and receiver–operator curves were constructed. Results: A total of 16 975 women were screened with a glucose challenge test, with pregnancy outcome information available for 1804 women who screened positive on glucose challenge test. With increasing plasma glucose values, there was a significant increase in pre-eclampsia, Caesarean section, shoulder dystocia and neonatal hypoglycaemia. Conclusions: The risk of adverse maternal and infant pregnancy outcomes increases with increasing levels of glucose impairment despite treatment.