During sex I noticed brown blood, what does that mean?

Answer 1

The brown blood is old blood and it could be an indicator of your period coming (depending on where you are in your cycle). Bleeding a little bit can also sometimes indicate an infection or if the body is stressed out about something regardless of whether the thing causing the stress is good or bad.

The only way to find out for sure what is going on is to see your doctor for further evaluation of the situation to see what they think is going on.