I have always been super active. Have done hitt training, running, Plyometrics, and heavy lifting for a long time. First pregnancy I stayed away from exercise first trimester since it was twins. Had a very smooth pregnancy overall. This time I started lightly walking fast up the hill last week. This morning I did a modified plyometrics workout, nothing crazy just 30 min. Two hours later started bleeding red. For 4 hrs straight. Saw my specialist who found a hematoma. They are very common he said and likely to resolve on their own. Too much activity and harder workouts can cause SCH which happened to me. The bleeding stopped after resting the rest of the day. Pay attention to your body. I thought I would be fine since I have done tough workouts for so long but clearly there are risks even for those of us that know what we are doing. Needless to say I am on restrictive activities until this resolves which could be weeks.