Dark brown period discharge may indicate sign of miscarriage
or old endometrial tissue with co-existence of vaginal infection
/ hormonal imbalance.
Here, you should undergo one blood test
for beta HCG & TVS scan (around 4-5 weeks) to confirm product of conception at the earliest. Early pregnancy
test may be negative.
After that, you can consult with gynecologist for next line of management for this condition. In exclusion of pregnancy, other relevant investigations like complete hormone assay, blood sugar, vaginal swab test, endometrial biopsy
etc are needed to be carried out.
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.
Be well & take care.