When you first start taking birth control (the pill) when is it affective?

How long do I have to use a back up form of Birth Control?When you first start taking birth control (the pill) when is it affective?
Current BC pills generally take 1 week to become effective, but you must check your packet or look up the name of the brand you are taking online so you can get exact information.
It usually takes a month to be effective. You have to use backup for at least the first pack. At the second pack you're safe.
OK i used birth control one time and i had a period for 2 months i went back to the doctors and she told me that will take up to three months for your body to get used to the pill, but as far as using back always use backup because you can still get pregnant on the pill if your body does not respond to the pill.