No. The appearance and consistency of your milk has nothing to do with its quality. If you are expressing breast milk, it won't always look the same. Changes in opacity and color are totally normal. As long as baby’s weight gain is on track, you have absolutely nothing to worry about. Also, if your baby has recently arrived, keep in mind that breast milk goes through some pretty drastic changes in the first few days of baby’s life. Your nutrient-rich first milk — called colostrum — is thick and often yellowish. As your mature milk “comes in,” your breast milk gradually transitions to look more like the cow's milk in your fridge.