Early universal screening of gestational diabetes in a university hospital in Thailand

A total of 1016 pregnant women attending antenatal clinic before 20 weeks of gestation during September 2018 to February 2019 were included in a cohort study with repeated cross-sectional assessments. The study was aimed to determine prevalence and characteristics of gestational diabetes mellitus (GDM) and pregnancy outcomes by early universal screening approach. GDM screening was performed during first visit and repeated during 24-28 weeks of gestation, as necessary, using a 50-g glucose challenge test followed by a 100-g oral glucose tolerance test for GDM diagnosis. Overall prevalence of GDM was 18.6%. A significantly higher prevalence of GDM was observed among high-risk than low-risk women (21.3% vs. 13.1%, p = 0.002). GDM among low-risk women contributed to 23.3% of all GDM cases. The majority of GDM (76.2%) were diagnosed before 20 weeks of gestation, with 74.5% occurring in high-risk women and 81.8% occurring in low-risk women. When initial screening tests were normal, risk of GDM diagnosed during 24-28 weeks was 6.0% (7.5% among high-risk women and 3.1% among low-risk women). Compared to those without GDM, women with GDM significantly had lower gestational weight gain (p < 0.001), higher prevalence of preeclampsia (p = 0.001), large for gestational age (LGA) (p = 0.034) and macrosomia (p = 0.004). These outcomes were more pronounced among high-risk women with GDM. Impact StatementWhat is already known on this subject? Universal GDM screening is recommended during 24-28 weeks of gestation, either by 1- or 2-step approach. Some also recommend early GDM screening among high-risk women. Prevalence of early-onset GDM varies between studies and benefits of early diagnosis and treatment are still controversial.What do the results of this study add? Early universal GDM screening identified more women with GDM and majority could be diagnosed before 20 weeks of gestation. GDM among low-risk women contributed to 23.3% of all cases. Adverse pregnancy outcomes were more common among high-risk women with GDM. This approach could be useful and can be implemented in other settings, especially those that serve high-risk population or with high GDM prevalence.What are the implications of these findings for clinical practice and/or further research? Early universal GDM screening should be considered in settings with high prevalence of GDM and high-risk women. However, benefits of early detection and treatment of GDM should be determined in more details in the future, especially in terms of cost-effectiveness and improvement in pregnancy outcomes.