Last depo-provera shot 9mnths ago not pregnant no stds stil no period but random brown spotting or smears what is it?

Normal spotting: It is common for lost of periods and random spotting when using depo. Each woman is different and after stopping, it can take months even a year for normal periods to return. Depo contains Progesterone only. This leads to a thin lining of the uterus that takes time to rebuild. The ovaries are suppressed so the ovary-brain feedback loop must restart. Pregnancy is possible so see your doctor.