Have you had much pain? From what I know brown blood is because it isn't coming out as quickly so when you finally see it the color may look brown. This sometimes can be a sign of a problem but not always. If you are feeling scared or worried talk to your doctor.
Otherwise you might want to let it run its course. I know I get sis on my ovaries and this has caused the brown coloring. The doctor told me to let it run its course but if pain became too intense or goes on for an extended time to come back in. I hope this helps...may God bless you