If you are sexually active, then late period with brown bloody discharge may indicate implantation
bleeding. Other associated factors are hormonal
imbalance and old endometrial tissue with vaginal infection
Therefore, you should undergo one home pregnancy
test with urine initially to check pregnancy status. One blood test
for beta HCG & TVS scan is required to confirm product of conception.
After that, you can consult with gynecologist for next line of investigation & management.
For direct consultation with me, you may visit my profile on http://www.healthcaremagic.com/doctors/dr-soumen-patra/63326. Here, you can upload image for more suggestion.