The expiration date on any medication helps determine whether the product is safe and effective. At this point, manufacturers can no longer guarantee that the drug isn't deteriorating. Because of this, taking expired birth control pills may result in an unwanted pregnancy.
Also asked, how long does it take for birth control to get in your system?
It depends on when you start taking them. You can take your first birth control pill any day of the month, but you may need a backup birth control method (like condoms) for the first 7 days. If you start combination pills within 5 days after your period starts, you'll be protected from pregnancy right away.
Is the pill still effective on your week off?
Yes. When you're on the pill, it's okay to have sex anytime, even during your period week — the week when you don't take the pill or take placebo pills instead. As long as you've been taking the pill correctly and consistently, you're protected from pregnancy even during that off week.
How effective are birth control pills?
Birth control is a way for men and women to prevent pregnancy. There are many different methods of birth control, including hormonal contraception such as "the pill." Women take the pill by mouth to prevent pregnancy, and, when taken correctly, it is up to 99.9% effective.