With 17 percent of American women ages 15 to 44 currently using birth control pills, this type of hormonal contraception is one of the most popular and widely used. Birth control pills are also known as oral contraceptives or simply “the pill.”

What Is It?

Birth control pills are small tablets taken daily that contain hormones to prevent pregnancy. There are two types of birth control pills—combination pills and progestin-only pills. Combination pills contain the synthetic hormones estrogen and progestin, while the progestin-only pills do not contain estrogen.

How Does It Work?

Like all methods of hormonal contraception, birth control pills essentially prevent ovulation (the release of and egg from the ovaries). Consequently, pregnancy cannot occur because there is no egg for the sperm to fertilize. As added measures, the hormones in birth control pills also thicken the cervical mucus to thwart off sperm and thin the lining of the uterus to prevent implantation of the egg. 

How Do I Use It?

You need a prescription to use birth control pills. Visit your doctor or a healthcare clinic to discuss what type of birth control is right for you.

Combination pills come in packs of either 21 or 28 pills. On pill is taken each day at the same time of day. With the 21-day pack, you will not take any pills for the last seven days of the month. With the 28-day packs, the last seven pills are tablets that contain no hormones but are taken to help you stay on a pill-taking routine.

Progestin-only pills come in packs of 28, and you must take one pill each day at the same time every day. All progestin-only pills contain hormones. With both types of birth control pills, the last seven days of the pack is when you will get your period.


If taken correctly, birth control pills are extremely effective in preventing pregnancy. Combination pills are more than 99 percent effective, while progestin-only pills are 98 percent effective. However, the pill must be taken every day at the same time to be effective.


Birth control pills offer a convenient, safe, and effective way to prevent pregnancy. Both combination and progestin-only pills also help regulate the menstrual cycle and reduce cramping. Combination pills are sometimes used to help clear acne or protect against health issues like bone thinning, infections, cysts, and even some cancers. In addition, the pill does not interfere with your ability to get pregnant in the future.


Birth control pills do not protect against sexually transmitted diseases. In order to be effective, the pill must be taken every day at the same time. Some women find it hard to remember to take the pill, which makes it ineffective in preventing pregnancy. Every woman reacts differently to the hormones in birth control pills. Some women experience side effects like change in sex drive, nausea, bleeding between periods, and breast tenderness. There are also very rare cases of blood clotting, stroke, and heart attack as a result of birth control pills. Overall, birth control pills are safe, but some women may be at increased risk for side effects. Talk to your doctor about these risks before taking birth control pills.