Preheat oven to 350 degrees F (175 degrees C). Grease a loaf pan.
Mix flour, sugar, baking powder, and salt in a large bowl. Stir milk, oil, egg, and vanilla extract into flour mixture until batter is just blended. Gently fold blueberries into batter; pour into prepared loaf pan.
Bake in the preheated oven until a toothpick inserted into the center comes out clean, 60 to 70 minutes.
