I too have been dealing with the annoying brown spotting on and off for about 4-5 years. I was on various types of birth control to try to treat...I had the most success with FemConFE since it has a higher amount of hormones, but I still had spotting btw periods, just less of it. I was also on spironolactone with the BC for acne, and it its known to cause irregularity. But that's what the BC is supposed to control. Anyhow, I thought, why not just stop everything for a while and see what happens? So, I got a copper non-hormonal IUD and stopped taking all meds for about a year or so. Still had spotting, I'd say about 18-22 days out of the month, and I had no idea when my period was. My GYN tried the progesterone thing, to no avail. Meanwhile, my acne got really out of control. Went to an endocrinologist and all of my hormone levels were normal. He just said my uterine lining was really thin, so he gave me some estrogen patches to wear for a few weeks, then I used the progesterone cream for a few weeks....and ....ohmygod....I started to have a decrease in spotting. I also started taking 400IU of Vitamin E every day as I've seen that sometimes helps with spotting associated with an IUD. So, then I had a period about ever 6 weeks or so with a lil (like 3-5 days) of spotting before and after. It was bliss! Except I had a pizza face. Back to spironolactone. Didn't really have spotting issues with it either for about 5 months. Now it's returning. :-( So, here's how I deal with it:
If I take ibuprofen several times through out the day for a couple of days, it does decrease, to just a couple spots when wiping. But of course, you can't just take ibuprofen all day every day.
I use a Diva Cup on my spotting days...this catches most of it, I don't have to deal with tampons, and I don't have to deal with awkward, soggy pantyliners. I take it out at night. Usually most of the gunk has been collected in the Diva Cup, so I'm kinda spot free for the night. And I'm usually okay during sex, as long as I've had the cup in for several hours before had.
During my actual period, I just use tampons, because I get scared I'll accidentally yank my IUD out as my cervix is lower during the period.
It's not totally ideal, but it works. And my husband is pretty understanding. We still have sex...just...no oral unless I'm spot free :-( But hey. I do get lucky once in a while. ;-)
Hope that helps!