If a pregnancy occurs while on mirena (levonorgestrel) will your doctor terminate the pregnancy if the fertilized egg isn't attached ?

Your choice.: If a pregnancy is this early, it would be difficult to diagnose. At that stage of development, a pregnancy test & ultrasound might be negative and a physical exam normal. If, however, pregnancy has advanced sufficiently to be diagnosed, your doctor can terminate it. Or you could have the Mirena (levonorgestrel) removed and keep the pregnancy. The Mirena (levonorgestrel) isn't harmful to a normal pregnancy in any case.