INTRODUCTION: Recent studies identified an increased risk of adverse perinatal outcomes in women who have one abnormal value on the 3-hour 100-g glucose tolerance test (GTT) compared to women without gestational diabetes (GDM). Limited data are available on the benefit of diabetic intervention with these patients. We examined outcomes of pregnancies diagnosed and managed with GDM based on one abnormal value compared to those receiving routine care. METHODS: We performed a retrospective cohort study of all women with one abnormal value, comparing outcomes for those patients who received routine prenatal care (January 2016 to February 2018) versus those treated for gestational diabetes (March 2018 to July 2021). The primary outcome was birth weight greater than 4,000 g. Secondary outcomes included large for gestational age and cesarean delivery secondary to labor dystocia. Nonparametric tests were used to compare outcomes between groups. Study was IRB exempt. RESULTS: One hundred twenty-six women had one abnormal value on the 3-hour GTT. 76 (55.88%) were diagnosed with GDM and managed accordingly, while 50 (36.76%) were followed with routine care. Of the women diagnosed with GDM, 27 (35.52%) required pharmacologic treatment. Diagnosis of GDM and intervention were associated with a significant reduction in birth weight greater than 4,000 g (5.26% versus 20%, odds ratio 0.22, 95% CI 0.07–0.75). There were no significant differences for secondary outcomes. CONCLUSION: Pregnancies with one abnormal value on 3-hour GTT who received diabetic intervention were less likely to have birth weights greater than 4,000 g. Although further studies with larger cohorts are needed, this supports the use of one abnormal value for the diagnosis of GDM.