Can you get pregnant the week after placebo pills if you've started taking the active pills in a new pack after your last placebo in your old one?

Unlikely: If a woman is on birth control pills, took all the pills in the pack, finished the placebo pills and just started a new pack of pills she should not be at risk for pregnancy. She should be well protected. There would only be chance of pregnancy if she started the new pack and was late by several days, or if she missed a number of pills in the previous pack.

Already effective: If you start the first pack of pills at the time of your period, they are immediately effective. If you start the first pack of pills at any other time, they are effective after one week. Since you are on your second pack, they are already effective. Please keep in mind that there is a small failure rate.