I've had the mirena (levonorgestrel) for 4years. I have a constant discharge no odor. I have a no period. My obgyn test all come back normal. Should I be worried?

It depends. It depends what it looks like. Some clear or milky discharge can be normal. Spotting is also common. Tan, green or thick white discharge should be checked. Not having a period while using Mirena (levonorgestrel) is very common especially after the first year. If your testing has been normal it doesn't sound like there is anything to worry about. Remember, Mirena (levonorgestrel) has to be removed or replaced in the us @ 5yrs.