Early Pregnancy Glucose Screening Is the Preferred Method for Diagnosing Gestational Diabetes Mellitus

Abstract

In our prior studies in the United States, we found that (1) 1 st -trimester oral 1-hour 50-gm glucose screening test results are highly correlated with 3 rd -trimester values, 2 and (2) the positive predictive value of an oral 1-hour 50-gm glucose screening test result >135 mg/dl administered between weeks 14-18 of pregnancy is 55% for the diagnosis of gestational diabetes, with an overall mean sensitivity of 84%. 3 In the current study by Kushtagi and Mahto, an early glucose screening test result >140 mg/dl before 20 weeks of pregnancy occurred in 29% of gravidas and resulted in a sensitivity of 78% with a positive predictive value of 44% for gestational diabetes mellitus before the 3 rd -trimester. In our previous study, we found that only 15% of gravidas had an oral 1-hour 50-gm glucose screening test result >135 mg/dl at 16 ± 2 weeks of pregnancy and that 37% of these early screen-positive women were diagnosed with gestational diabetes by follow-up 3-hour 100-gm glucose tolerance test in advance of the 3 rd trimester. 3 Of particular importance is that the populations investigated in our two U.S. studies were comprised of women of different racial and ethnic backgrounds (Caucasians, Blacks, Filipinos, Orientals, and Pacific Islanders) than the population studied by Kushtagi and Mahto in India. 2,3 We view the current study as confirmatory of the universal applicability of the early pregnancy glucose screening approach for identifying gestational diabetes mellitus in gravidas of all racial and ethnic groups.