Discharge

Almost 11 weeks...(Thursday is 11 weeks) two weeks ago I had brown spotting. Nothing major. It was like dry brown spots on panty liner. No clots, no mucous, nothing just the spots and it was never enough to even fill a panty liner. It had stopped by that evening. Started again two days ago same thing and had stopped by that evening. Any guesses? This is my fourth pregnancy. Never experienced this with my other three. I just had a baby 7 months ago and I’m almost 3 month pregnant now. One hell of surprise since tubes were supposedly tied.