A Revolution in Birth Control

And every year that's gone by another baby's come

There's gonna be some changes made right here on nursery hill

You've set this chicken your last time 'cause now I've got the pill

— Loretta Lynn, "The Pill"

In 1975, Loretta Lynn was banned from some Nashville radio stations for her daring tribute to reproductive self-determination. Yet today, the birth control pill is used by more than 110 million women worldwide. Since it was first approved by the FDA in 1960, the pill has granted billions of women the power to control their own fertility.

Overtaking the diaphragm and IUD, the pill quickly became the most popular woman-controlled reversible form of contraception in history. In the U.S. alone, nearly 12 million women use the pill — that's nearly 20 percent of women of reproductive age. Eighty-two percent of women in the U.S. use the pill at some point in their lives. Despite the pill's popularity, many women who use it or are interested in using it have questions that go unanswered. Here's what you need to know about this common method of birth control:

How effective is the pill?
When used correctly — taken every day, at the same time each day — the pill is up to 99.7 percent effective against pregnancy. It is especially important to take the pill at the same time each day if you are taking progestin-only pills.

How exactly does the pill work?
The pill contains hormones similar to the estrogen and progesterone made by a woman's ovaries. These hormones work to prevent the ovaries from releasing an egg (ovulation). They can also thicken cervical mucus to prevent sperm from joining with an egg. Combined hormone pills are more likely to prevent ovulation, while progestin-only pills are more likely to thicken cervical mucus.

How much does the pill cost?
Nationwide, the cost for a monthly package of pills ranges from $20 to $35. Costs vary from community to community, based on regional and local expenses. The cost usually is less at a clinic and is covered by Medicaid. Before a clinician will prescribe the pill, an initial gynecological exam may be needed, which usually ranges from $35-$125.

When does the pill start working?
If you start taking the combination pill within five days of the start of your period, pill protection begins immediately. If you start taking it at any other time, pill protection begins one week later. You may start the progestin-only pill at any time. Protection will begin after two days. Use a backup method — like a latex or female condom — until pill protection starts.

Will the pill prevent me from getting pregnant in the future?
No. A woman may become pregnant as soon as she stops taking the pill.

I've heard the pill makes you gain weight. Is that true?
Everyone is different, and all women who take the pill have different experiences — some women gain weight, some lose weight, and others have no change in weight. Other possible side effects include bleeding between periods, breast tenderness, nausea (and rarely, vomiting), and changes in mood. These side effects usually clear up after two or three months of using the pill; if not, consult the clinician who prescribed the pill. Serious problems, including blood clots and high blood pressure, are rare. On the other hand, there are numerous non-contraceptive benefits that come along with using the pill, including, less acne, more regular periods, and less PMS.

I missed a pill. What should I do?
Check out this chart to see what to do if you forget a pill or two. And when in doubt, use a backup method of birth control.

If I'm taking other medication, can it affect how well the pill works?
Other medications can affect the pill. If you are taking other medications, check with your clinician about the effectiveness of the pill.

Are there any women who can't take the pill?
Smokers, especially if they are 35 or older, shouldn't take the pill because of increased risk of heart attack or stroke. Women with certain other medical conditions, including certain kinds of diabetes, cancers of the breast or uterus, uncontrolled high blood pressure, or a history of blood clots or vein inflammation, are also not able to take the pill.

Can I use the pill to skip my period?
Yes, you can use combination pills in order to avoid having your period, although it's a good idea to speak with a clinician if you plan to do so. Traditional combination pill packs contain 21 active pills and seven reminder pills. The reminder pills are placebos that contain no hormones to prevent pregnancy. Other combination pill packs contain only 21 active pills — a woman waits eight days after finishing her pack to start the next pack. You can skip your period by continuously taking active pills — begin a new pack of pills the day after finishing the 21 active pills in a pack.

Planned Parenthood is a trusted provider of the pill. For prescriptions and other health services, call 1-800-230-PLAN to find a clinic near you.