Screening for gestational diabetes at antenatal booking in a Malaysian university hospital: The role of risk factors and threshold value for the 50-g glucose challenge test

Background: The best method of screening for gestational diabetes (GDM) remains unsettled. The 50‐g glucose challenge test (GCT) is used in a two‐stage screening process but its best threshold value can vary according to population. Aims: To evaluate the role of risk factors in conjunction with GCT and to determine an appropriate threshold for the one‐hour venous plasma glucose with the GCT. Method: In a prospective study, 1600 women at antenatal booking without a history of diabetes mellitus or GDM filled a form on risk factors before GCT. Women who had GCT ≥ 7.2 mmol/L underwent the 75‐g oral glucose tolerance test (OGTT). GDM was diagnosed according to WHO (1999) criteria. Result: Thirty‐five per cent had GCT ≥ 7.2 mmol/L, 32.6% underwent OGTT and 34.5% of OGTT confirmed GDM. The GDM rate in our population was at least 11.4%. Examination of the receiver operator characteristic curve suggested that the best threshold value for the GCT in our population was ≥ 7.6 mmol/L. Multivariable logistic regression demonstrated that only GCT ≥ 7.6 mmol/L was an independent predictor for GDM (adjusted odds ratio 3.7: P