The 2024 Flemish consensus on screening for gestational diabetes mellitus early and later in pregnancy

Screening for gestational diabetes mellitus (GDM) is important to improve pregnancy outcomes and to prevent type 2 diabetes after pregnancy. Due to a lack of evidence, the 2019 Flemish consensus did not recommend screening for GDM in early pregnancy. Recently, a large randomized controlled trial (TOBOGM) demonstrated that screening for GDM before 20 weeks reduces the risk of neonatal complications in women with risk factors when using higher cut-offs to define GDM compared to the criteria used later in pregnancy.

Based on this new evidence, members of the Diabetes Liga, the Flemish associations of general physicians (Domus Medica), obstetricians (VVOG), midwives (VBOV), diabetes nurse educators (BVVDV), dieticians (VBVD) and clinical chemists (RBSLM) have adapted the Flemish consensus on screening for GDM.

Recommendations: As in 2019, this new consensus recommends universal screening for overt diabetes in early pregnancy preferably by measuring fasting plasma glucose by using the same diagnostic criteria as in the non-pregnant state. Based on the new evidence, women with fasting plasma glucose 95-125 mg/dL (5.3-6.9 mmol/L) before 20 weeks gestation should be diagnosed as early GDM. In addition, in women with obesity and/or a history of GDM, it is advised to perform already a 75 g oral glucose tolerance test (OGTT) between 6 and 20 weeks gestation using higher cut-offs to diagnose early GDM [fasting ≥95 mg/dL (5.3 mmol/L), 1 hour ≥ 19 mg/dL (10.6 mmol/L) and/or 2 hour ≥ 162 mg/dL (9.0 mmol/L))]. The recommendation concerning screening for GDM between 24 and 28 weeks remains unchanged with a diagnosis of GDM based on the 75 g OGTT and IADPSG criteria [fasting ≥ 92 mg/dL (5.1 mmol/L), 1 hour ≥ 180 mg/dL (10.0 mmol/L) and/or 2 hour ≥ 153 mg/dL (8.5 mmol/L)].