I am going back on ortho-tricycline lo after not having been on it for over a year. My periods have been irregular in the meantime and my last period started january 12th. I haven't started my period yet this month, but I would like to start taking the pill today anyway. I have two questions:

1) will this hopefully prevent me from getting my period until three weeks from now when I start the inactive green pills? (breakthrough spotting is okay, but I would like avoid a full-on menstrual flow if possible.)

2) will this still be an effective method of birth control 7 days from now?

I would really appreciate any help with this, thanks!