Protein-bound fucose was measured in the serum of women in two conditions: (1) during and after pregnancy, and (2) before and during oral contraceptive therapy. These measurements were made during oral glucose tolerance test (6 hr for pregnant group; 3 hr for oral contraceptive group). While the glucose and insulin levels fluctuated with time, the serum fucose levels were constant. Both glucose and insulin levels were altered by the two conditions studied, but the serum fucose was not.