L.S.
I had spotting at 9 weeks and then again at 13 weeks with my first pregnancy and gave birth to a healthy, beautiful baby girl. Spotting is quite common, but with her history she should go and see her doctor sooner rather than later.
We actually went to the ER when I was spotting at 13 weeks (I'd actually passed a clot about the size of my thumbnail), and that was when I first got to hear her heartbeat :)