Hi,
Welcome to ehealthforum,
Brown discharge could be suggestive of infection, cervical problems, PID, pregnancy (implantation bleeding) etc. The exact cause can only be made out after careful examination and further investigations done by your doctor/gynecologist. If pregnancy is suspected, consider visiting your gynecologist for further examination (to confirm pregnancy related changes/signs in body) and a blood/serum HCG level test (to confirm/rule out pregnancy accurately). Wait and watch for your next periods. Look out for development of any new symptom suggestive of early pregnancy if you suspect to be pregnant. Drink plenty of water. Take adequate rest. Maintain healthy diet.
Take care.