N.P.
Brown blood is perfectly normal and very common in many women, it's just "old blood" and tends to either precede or follow the red blood. It tends to be light, not heavy. But sometimes it can be "chunky". I know, eww right? It can also make up the majority of the period in some people.
Blood is a specialized bodily fluid that is composed of a liquid called blood plasma and blood cells suspended within the plasma. The blood cells present in blood are red blood cells, white blood cells and platelets. We have red blood, which is bright red when oxygenated, due to hemoglobin.
When the blood breaks down, the oxygen concentration is reduced and the plasma, which is mostly water, by concentration, is released. Therefore, the blood is not as red and not as bright - thus it appears brown.
I had heavy gross periods for about a year after I had my daughter. They were never really the same but they did get better over time.