There are times when we have intermittent bleeding, brown is old blood which may be lingering from your last period. Or if you are on BCP's it's breakthrough bleeding. Either way it means nothing, it's just older blood. Fresh blood is obviously bright & red, left exposed to air within a few hours it turns.

Let us just say that it is not unusual. If it keeps up, then talk to your doctor but most women do experience this from time to time. As sera pointed out it is remnants of your last period. For whatever reason you did not get a complete "flush."

No particular time... maybe a day or so.

Maybe a day; maybe a week. If it does not stop, then contact your doctor.

If the only symptom you are having is the dark scant bleeding, I would doubt it secondary to an infection. Cervicitis in an inflammation or infection of the cervix, it can also be caused from trauma to the cervix. Generally there are other symptoms such as itching, abdominal pain, painful intercourse, etc. However, this is something only a gyn doc can rule out. He/she needs to take a look.

There are random months were this type of bleeding will just start, it goes away in a few days and is scant in nature. It's just more annoying and attributed to a "left over" period, where the body did not rid it's self of everything during the normal period. Most have it occur a handful of times and it's nothing to concern yourself with.

If it's got you bothered see the doc but do not jump in to believing you have a disease, especailly without the presence of other symptoms. RELAX.