Birth Control Hormones: The Pill

Topic Overview

What are combination pills?

Combination pills are used to prevent pregnancy. Most people call them "the pill."

Combination pills release a regular dose of two hormones, estrogen and progestin. They prevent pregnancy in a few ways. They thicken the mucus in the cervix. This makes it hard for sperm to travel into the uterus. And they thin the lining of the uterus. This makes it harder for a fertilized egg to attach to the uterus.

The hormones also can stop the ovaries from releasing an egg each month (ovulation).

You have to take a pill every day to prevent pregnancy.

There are different kinds of packages for these pills. The most common one has 3 weeks of hormone pills and 1 week of sugar pills. The sugar pills don't contain any hormones. You have your period on that week. But other packs have no sugar pills. If you take hormone pills for the whole month, you will not get your period as often. Or you may not get it at all.

How well do they work?

In the first year of use:^{footnote 1}

• When combination pills are taken exactly as directed, fewer than 1 woman out of 100 has an unplanned pregnancy.
• When pills are not taken exactly as directed, such as forgetting to take them sometimes, 9 women out of 100 have an unplanned pregnancy.

Be sure to tell your doctor about any health problems you have or medicines you take. He or she can help you choose the birth control method that is right for you.

What are the advantages of combination pills?

• These pills work better than barrier methods. Barrier methods include condoms and diaphragms.
• They may reduce acne and heavy bleeding. They may also reduce cramping and other symptoms of PMS (premenstrual syndrome).
• The pills let you control your periods. You can have periods every month or every few months. Or you can choose not to have them at all.
• You don't have to interrupt sex to use the pills.

What are the disadvantages of combination pills?

• You have to take a pill at the same time every day to prevent pregnancy.
• Combination pills don't protect against sexually transmitted infections (STIs), such as herpes or HIV/AIDS. If you aren't sure if your sex partner might have an STI, use a condom to protect against disease.
• They may cause changes in your period. You may miss periods, or you may have spotting or a little bleeding. If you miss a period, find out if you are pregnant.
• They may cause mood changes, less interest in sex, or weight gain.
• Combination pills contain estrogen. They may not be right for you if you have certain health problems.