Using fasting plasma glucose concentrations to screen for gestational diabetes mellitus: prospective population based study

Objective To evaluate whether measuring fasting Plasma glucose concentratio n is an easier screening procedure for gestational diabetes mellitus than t he 1 hour 50 g glucose challenge test. Design Prospective population based study. Setting Outpatient clinic in a university hospital. Participants 520 pregnant women (328 (63%) white, 99 (19%) Asian, 31 (6%) A frican, 62 (12%) others) with mean age 28.4 (SD 0.2; range 17-45) years. Al l underwent a glucose challenge test between the 24th and 28th gestational week, followed by a diagnostic 3 hour 100 g or al glucose tolerance test wi thin one week. This was done irrespective of the result of the challenge le st. Main outcome measure Receiver operating curves were used to determine the b est cut off values for screening with fasting plasma glucose concentrations , Results Fasting plasma glucose concentration at a threshold value of 4.5 mm ol/l and the glucose challenge test with a threshold value of 7.8 mmol/l. y ielded sensitivities of 81%, and 59% respectively and specificities of 76%, and 91% respectively Measuring fasting plasma glucose concentration as a s creening procedure required a diagnostic test in 30%, compared with 14% whe n the challenge test was used. Conclusions Measuring fasting plasma glucose concentrations using a cut off value of greater than or equal to 4.8 mmol/l is an easier screening proced ure for gestational diabetes than the 50 g glucose challenge test and allow s 70% of women to avoid the challenge test.