How to Effectively Use Your Birth Control Pills

Birth control pills—often known as "the pill"—have been touted for their reliability. Experts estimate that they're more than 99 percent effective when taken as directed. But there's a big caveat here: Women need to take their contraceptives consistently and correctly to prevent pregnancy.

Starting a Regimen

You may begin taking your pills at any time during your cycle. When you start a combination pill—meaning one that contains both estrogen and progestin—within five days after the beginning of your menstrual period, you're protected from pregnancy immediately. If you start taking the pill at any other time of the month, you'll need backup contraception for a week, so plan to use a condom, female condom, sponge or diaphragm if you have sex during that first week.

Women who are prescribed progestin-only pills, sometimes called the minipill, can also begin taking them at any time but will need to use additional birth control for two days afterward.

If you want to start taking the pill after pregnancy or while breast-feeding, talk with your health care provider about your options. The progestin-only pill may be used immediately after childbirth and while nursing, but there is a recommended waiting period for combination pills.

Day-to-Day Use

Combination pills most often come in a 21-day or 28-day pack. If you have the latter, the package likely comes with seven reminder pills, sometimes called placebos, which contain no active ingredients and are only meant to help you stay on track. You should have your period while taking these pills. When taking the 21-day form, you will simply not take pills during the last week of your cycle, during which you will have your period.