I had nasty brown discharge and blood for most of my first trimester. It turned out that the fish oil I was taking was thinning my blood too much. I stopped taking it and the bleeding stopped. If you are taking DHA, that can do the same thing. I'm not saying it's dangerous because I don't know, but seeing the blood was enough to make me quit taking it. If you arent taking any supplements, try to avoid any strain or sex. It made mine worse, even straining on the toilet. Don't freak out though its really common.