Objectives: To ascertain prepregnancy physical activity and dietary intake from a sample of women in early pregnancy and estimate the effect of prepregnancy lifestyle behaviors on the 1-hour glucose challenge test (GCT). Methods: We conducted a prospective analysis of a racially diverse urban-based sample of 152 pregnant women in the first trimester who were participants in the Parity, Inflammation and Diabetes (PID) study. Dietary intake before pregnancy was assessed using a modified version of the Block Rapid Food Screener, and leisure time physical activity before pregnancy was assessed using the Baecke questionnaire. Test results from a nonfasting oral GCT conducted between 26 and 28 weeks were abstracted from the medical record. Participants were classified as having a positive GCT if the blood glucose measurement was ≥140 mg/dL and as negative with a blood glucose measurement