Hi, I have been having the same issues. Did you ever find out the cause?
I have had the same exact problem for the last three months. 3 or 4 days before my period I experience swelling and uncontrollable itch. Nothing works.. I am about to make an appointment with my OB/gyn..I know it cannot be an STD becuz I never have unprotected sex and I do not have it on a regular..I know it is not the liners or tampons becuz I absolutely NEVER use the scented ones..I also assumed I had a yeast infection the first month but this is ongoing..The second month was accompanied by a urinary tract infection.. By the time I heal up completely..its time for my menstrual cycle to begin again and the agony just repeats itself!! I hope we can find some type relief..
What kind of protection do you use when you are on your period? Pads or tampons? I find that some liners don't agree with my vagina and I get a pesky external itch on the outer labia--especially if they are the scented kind but certain brands can affect me as well.
The pH in the menses blood usually makes things right as rain. When I'm getting a yeast infection, for example, after my period--everything is back to normal. Sassy is right, maybe it's the form of bc you're on that is causing an adverse effect.
I think you need to see a gyn about this, sounds like your body is not liking the pill you are on.