Preheat oven to 400 degrees F (200 degrees C). Grease and flour muffin pan or use paper liners.
Mix the flour, oats, sugar, baking powder, salt, cinnamon, and nutmeg together in a mixing bowl until evenly blended. In a separate bowl, stir together the pumpkin, milk, egg, and butter. Gradually stir in the flour mixture, just until all ingredients are moistened. Fold in the blueberries. Spoon batter into muffin cups, filling to the top.
Bake in preheated oven until tops spring back when lightly pressed, about 20 minutes.
