What causes a missed period with mirena (levonorgestrel)? hpt negative, 3 days late, had sono and showed 0.76cm endo and 2cm dominant follicle.

Side effect: Mirena (levonorgestrel) is an IUD that uses hormones to prevent pregnancy. A common side effect of this is women ceasing to have menstruation (amenorrhea). Particularly common if you're thin/petite. You may still notice other signs of your period even without vaginal bleeding as the IUD effect is primarily regional compared the oral pills that effect the entire body.