During early pregnancy, the uterus is doing an awful lot of hard work! It is stretching and adapting to its new "job" of playing host to your growing baby! Sometimes, old blood that was still in the uterus is expelled in that process. This is what causes brown spotting. The very fact that the amount of blood that leaves your body is minimal, and that it is brown or even black in color, is enough to inform you that it is old blood. As long as you are not having any other symptoms such as pain or cramping, and the amount of blood is minimal, you should have no reason to worry. If your bleeding is not brown in color, but bright red, and you are experiencing a flow of blood that increases over time, you do need medical assistance however, as this can signify the start of a miscarriage.
Heavy bleeding with cramping and pain warrants an immediate call to your doctor. Unfortunately, there is not much, if anything, doctors can do to stop a miscarriage from happening, but if you are bleeding, ruling out an ectopic pregnancy is a good idea. Pregnancy teaches us so much about our bodies, and in a way prepares us for being mothers. A few years down the line, when you are in the process of potty training your toddler, you will not bat an eyelid at the various bodily fluids that are an everyday occurrence when you are a parent!