Role of the fasting plasma glucose in diagnostic algorithm of gestational diabetes

The International Association of Diabetes in pregnancy study groups (IADPSG) recommends all pregnant women to undergo oral glucose-tolerant test between 24 and 28 week of gestation. This might be expensive for the national health system and could overload the laboratory Furthermore, fasting plasma glucose (FPG) < 4.4 mmol/l is associated with very low risk of adverse pregnancy outcome.

Objective: Aim of the current study is to determine the prognostic value of FPG in the diagnosis of gestational diabetes (GDM) according to the criteria of IADPSG and American Diabetes Association (ADA).

Methods: In the study were included 572 pregnant women between 24 and 28 week of gestation. Two thresholds of FPG were used to rule in or rule out the women into diagnosis of GDM.

Results: According to IADPSG and ADA criteria, GDM was found in 181 (31.6%) and 77 (13.5%) women respectively (p<0.001). FPG thresholds of > or = 5.1 mmol/l ruled in GDM in 132 (23.1%) women with 100% specificity, while < 4.4 mmol/l ruled out GDM in 159 (27.8%) women with 95.6% sensitivity. If we decide to continue with OGTT in those women with FPG > or = 5.1 mmol/l to confirm the diagnosis, at least in 27.8% (159) OGTT could be avoided, because of the FPG < 4.4 mmol/l.

Conclusions: The IADPSG criteria increased GDM prevalence 2.4 fold. Taking into account the FPG is beneficial and cost-effective. It could simplify the IADPSG diagnostic algorithm.