Brown discharge with no period or after sex can have other causes ... You might also notice fluid or tissue passing from the vagina. You might not need any treatment if a miscarriage occurs ...

When your period first starts, you may see pink or brown discharge, and it continues to ... irritated vaginal tissue, ...

Brown discharge can happen at the beginning and end of your period because the blood oxidizes. It can also be a sign of certain STIs like chlamydia and gonorrhea or pelvic inflammatory disease.