Most doctors would counsel you to wait a full month before trusting them fully. Although most Dr.S always say to use another form of bc along with birth control pills to be safe. If you are absolutely positively not ready for a child, I would use at the very least some spermacide just to be careful. I just know way too many people who have become a statistic in the 1% of women who get pregnant while using the pill correctly. Hehe
Well the rx says a week.... The patch says at as well if you start within 24hrs of your period.... But to be extra cautious, (as we all should) I would wait a month. Everyones body is different and a week may not be enough for your body to be regulated by the pills.