It was determined that I had low levels of progesterone, thus making it difficult for the pg to "stick" early on. I took natural progest. cream 2x daily and also took the herb vitex, which is a natural hormone balancer, for one month while ttc. That cycle, I became pg, had some early spotting and cramping (around 7 weeks), which went away after some rest and drinking some nice red raspberry leaf tea. I continued to use the progest. cream 1x daily and vitex until about 15 weeks. I don't know whether the progest would stop *your* spotting and bleeding, but because I knew that I had low progest., I knew that supplements would likely help me along.
I did not find any good resources on the pros & cons of using progest cream, but did read somewhere that using cream that was natural and was not based on "wild yam" was easier for your body to use. if you do a search on MDC, i found a lot of discussion on the ttc boards from early spring '02. Good luck and congrats!!!