Objective: To evaluate the incidence of large-for-gestational age (LGA) newborn between pregnant women with abnormal and normal glucose challenge test (GCT).

Design: Retrospective cohort study.

Material and Method: Two hundred and sixty pregnant women, who were at risk for gestational diabetes mellitus (GDM), received screening following practice guideline. The women were divided into two groups. The study group comprised of 130 women whose screening test results of 50-g 1-hour GCT were abnormal but had not been diagnosed with GDM (normal oral glucose tolerance test). The control group comprised of 130 women whose GCT results were normal. Comparison of various maternal and neonatal characteristics as well as the incidence of LGA between the groups was made.

Results: There were no significant differences in age, gestational age at first antenatal care, body mass index, and risk of GDM between the two groups. The study group had a significantly higher number of parity and number of risk factors of GDM than the control group. There was no significant difference in the incidence of LGA newborn between the two groups (8.5% in the study group and 10.8% in the control group, p = 0.528). There were also no significant differences in gestational age at delivery, pre-eclampsia, pre-term delivery, hyperbillirubinemia of the newborn between the two groups. There were no cases of maternal acute postpartum hemorrhage, and birth asphyxia.

Conclusion: The incidence of LGA newborn was similar between non-GDM women with abnormal and normal screening GCT results in Siriraj Hospital.

Keywords: Gestational diabetes mellitus, Large-for-gestational age newborn, Glucose challenge test