how long till birth control works
1 You should use a backup method of birth control (condoms with spermicide) until you start the pill. You also will need to use a backup method of birth control (condoms with spermicide) during the first 7 days of the pill package.  Start your pills today. If you start your pills today, you should use a backup method of birth control (condoms with spermicide) during the first 7 days of the pill package. Birth control pills will start to protect you from pregnancy after the first week, if you take them correctly.