What might be the other problem if you are experiencing mild bleeding and dark brown odorless discharges, urinalysis is negative, pap smear negative?

Anovulatory: You may be having anovulatory, meaning "no egg", cycles. This causes some dark spotting instead of a regular period. This can start happening as you get closer to menopause. If it continues, your doctor might want to get an ultrasound of your uterus or possibly a biopsy. Don't worry, just keep track of when it happens and follow-up with your doctor. (and always carry pads or tampons!).