Background: first trimester glycemia ≥ 92 mg/dL is a valid criterion for diagnosis of gestational diabetes mellitus (GDM), excluding the requirement of Oral Glucose Tolerant Test (OGTT) later in pregnancy. Glycated Hemoglobin (A1C), is well stablished for diagnosis of diabetes mellitus, however its utility in the screening of GDM is not certain. The aim of this study was to associate A1C and glycemia values in the first trimester of pregnancy.

Methods: this was an observational retrospective study that included Brazilian women screened with A1C until 20 weeks of gestation between January 2009 and March 2019. Data were collected from a laboratory center. A1C was estimated by high-performance liquid chromatography. Exclusion criteria were hemoglobin < 11.0 and use of antidiabetic drugs or insulin. Women were divided into groups according to first trimester glycemia: <70; 70-85; 85-92; 92-126; ≥ 126 mg/dL. Primary outcome was association between A1C and glycemia values.

Results: a total of 17.764 women were included. The majority was in the 70-85 mg/dL group (9.689), followed by 85-92 mg/dL (5.420), 92-126 mg/dL (2.178), < 70 mg/dL (436) and ≥ 126 mg/dL (41). Means’ age were: 32.5 ± 4.79 (<70 mg/dL); 33.8 ± 4.14 (70-85 mg/dL); 34.2 ± 3.9 (85-92 mg/dL); 34.7 ± 4.03 (92-126 mg/dL) and 31.4 ± 3.46 years (≥ 126 mg/dL). Means’ Body Mass Index (BMI): 24.5 ± 2.68 (<70 mg/dL); 25.2 ± 3.88 (70-85 mg/dL); 25.8 ± 4.5 (85-92 mg/dL); 27.6 ± 4.83 (92-126 mg/dL) and 27.3 ± 2.59 years (≥ 126 mg/dL). A1C means were very similar in the first four groups: 4.92% ± 0.41 (<70 mg/dL); 5.01% ± 0.32 (70-85 mg/dL); 5.15% ± 0.32 (85-92 mg/dL) and 5.33% ± 0.42 (92-126 mg/dL). The group with glycemia ≥ 126 mg/dL presented A1C mean of 7.08% ± 1.49, significantly higher than all the other groups (p < 0.01 by Kruskal-Wallis test).

Conclusion: in this study, A1C values were not accurate to the screening of GDM in the first trimester of pregnancy. The main difference was in the group with glycemia ≥ 126 mg/dL, already defined as overt diabetes.

Disclosure

F. Faro: None. R.F. Ramalho: None. M. Pereira: None. J.E. Salles: Board Member; Self; AstraZeneca, Boehringer Ingelheim Pharmaceuticals, Inc., Lilly Diabetes, Novo Nordisk Inc. P.S. Rosa: None. M.G. Teles: None. P. de Sá Tavares Russo: None.

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