Dark brown discharge is usually seen at the beginning or end of your menses (period). It's also an indicator of bleeding that is possibly slow, or from a few days ago. It doesn't necessarily mean anything is wrong, but it would pay to discuss this with your primary care physician. Sometimes people get break-through bleeding, (yes, your body could be cleaning out, or you're having an irregular cycle) but since I'm a cancer survivor (ovarian - it comes with subtle warnings, and often bleeding is NOT one of them), I'm an advocate for getting abnormalities of the female anatomy checked out. It's better to rule out "NOTHING" than to leave SOMETHING to chance.
Even though you said you're a virgin, are you on an oral contraceptive pill, or have you recently changed pills? Breakthrough bleeding can occur then. I would strongly recommend taking an iron supplement as a boost while you're trying to figure out what's going on. I understand the cost involved in doctors etc, so if you're trying to rule things out yourself, please at least get some iron, so that you don't become anemic.
With regards to cervical polyps, I really don't think being a virgin matters. They can develop in any female, particularly pregnant women and those who are going through menopause (major hormonal changes).
Good luck. I hope you find your answer and can get your abnormal discharge sorted out and it's nothing serious.
Brown blood is old blood, and is usually shed right before, or right after a period - like you said - our body clearing itself out. Another thing it could be is a bacterial type infection. This isn't an STD so you can still catching it even though you're a virgin.
If it continues over days or longer then maybe an idea to see your doctor.
Oh, I forgot to add in that I am NOT on any birth control. I was considering it though because my periods last for 7 days and the first 3-4 days are relatively heavy.
Something like this has happned to me before but that was over a year ago. Now it's happening again. It's not like it consistently happens between every period, so I'm really hoping that it's nothing serious. Just some cleaning out that my body is doing.
I strongly recommend you talk to your doctor and request a pelvic exam (pap smear and abdominal check).
Not all women have a typical cycle and some do get break through bleeding, but if this is a fairly new development and you're not on birth control, you should see someone. If you're in the US and don't have insurance, or coverage through your parents then check with your county: they could have some programs specifically designed for womens' health.
It could be nothing, but if it's not normal for you, listen to your body. It's the best advice I can give anyone.
As Carly1306 said, it could also be a result of a bacterial infection, which can happen irrespective of sexual activity or not. Our bodies sometimes get out of balance and is nothing to be embarrassed about. It's just that nobody likes talking about this stuff because it's so personal.
If you have any concerns or just want to talk, please, by all means. I know it's disconcerting when something is going on that seems odd and you can't 'see' what it is.
I wouldn't be worried about having dark periods , I have them all the time since I've started my period when i was 12. Now I'm 25 with four kids, its just cleaning your body out and the doctor will give you a pap smear to see if there is anything going on, he did that and the test came back normal for me and after the test, I still have those periods. My periods are 3-4 days heavy, then two days off and then 4 days regualr then two days spotting. It's been line this since I had my new baby. But make sure u know ur body, even if u have to get two opinions then do it, its ur health don't let a doctor tell you what you want too hear. You want the truth. Not his wife expections or anything what his other patients are going through either. Make sure you write a list what you want too know and keep a record of it. Good luck. Hope your appt goes well :)