Does raising the glucose challenge test threshold impact birthweight in Asian gravidas?

Objective: Some authors suggest a glucose challenge test (GCT) threshold of 150 mg/dL in Asian gravidas. The impact of such a policy on outcomes is unknown. Study Design: A retrospective cohort of 1705 Asian graviclas. Subjects (n=95) had a GCT of 140-150 mg/dL and underwent a 3-h glucose tolerance test (GTT). Matched controls (n=190) had a GCT of < 140 mg/dL. Birthweight was the primary outcome and the secondary outcomes were cesarean delivery (CD) rate and macrosomia. Results: Eight subjects (11.9%) had gestational diabetes mellitus (GDM); none had GTT fasting values of > 90 mg/dL. Mean birthweight was 3282 g in the subjects and 3238 g in the controls (P=0.39). There were no significant differences in the secondary outcomes. Conclusion: Compared with controls, study patients did not deliver significantly larger infants. However, raising the GCT threshold would have missed 8 subjects (11.9%) with GDM. Raising the GCT threshold to 150 mg/dL in Asian graviclas may unacceptably lower the sensitivity of the screening test.