My girlfriend just started mircette, on a sunday start. The packaging says that the pill is effective after 1 week, a doctor at the student health center here on campus says it actually is only 3 days but 1 week is a safety margin, I called a couple other docs and they said 1 week, but her doctor said a month. It's a 28 pill package. What is true on this? I know some other pills don't take effectiveness for a month, (some for even longer? I dont know.) we had unprotected sex one time and although I pulled out, we're still kinda worried...Her period is supposed to start this week...She has some cramps, back pain, acne...All telling her its coming...But also her stoumach was hurting really bad last week. She just wants more input on this medicene.