Prevalence of Gestational Diabetes Diagnosed before 24 Weeks of Gestation

Objectives: To determine prevalence of gestational diabetes mellitus (GDM) diagnosed before 24 weeks of gestation (early GDM), to evaluate associated risk factors, and to compare pregnancy outcomes between different GDM status. Materials and Methods: A total of 480 women who started antenatal care before 24 weeks of gestation were included. All women received a universal 2-step approach for GDM screening and diagnosis during first antenatal care visit and repeat at 24 - 28 weeks of gestation. Data were extracted from medical records, including baseline, obstetric and antenatal care data, GDM risks, diagnosis of GDM, and pregnancy outcomes. Prevalence of overall GDM, early and late GDM were estimated. Various characteristics and pregnancy outcomes were compared between women without GDM, early, and late GDM. Results: Overall prevalence of GDM was 20%. Majority of GDM were diagnosed before 24 weeks of gestation (early GDM) with the prevalence of 14.4% which contributed to 71.9% of all GDM cases. Both early and late GDM were more likely to be overweight and have previous GDM. Early GDM significantly had lower gestational weight gain than those without GDM. Rates of large for gestational age (LGA) and macrosomia were slightly higher in GDM women than those without GDM. The only significant risk factor for early GDM was previous GDM with adjusted odds ratio 5.38, 95% confidence interval 1.16 - 24.92 (p = 0.031). Conclusion: Prevalence of early GDM was 14.4% which contributed to 71.9% of all GDM cases. Pregnancy outcomes were not significantly different between early, late GDM and those without GDM. The only independent associated factor was previous GDM.