What Is It?

The birth control patch is a thin, beige, 1¾-inch (4½-centimeter) square patch that sticks to the skin. It releases hormones through the skin into the bloodstream to prevent pregnancy. Hormones are chemical substances that control the functioning of the body's organs.

How Does It Work?

The combination of the hormones progesterone and estrogen in the patch prevents ovulation (the release of an egg from the ovaries during a girl's monthly cycle). If an egg isn't released, a girl can't get pregnant because there's nothing for a guy's sperm to fertilize.

The hormones in the patch also thicken the mucus produced in the cervix, making it difficult for sperm to enter and reach any eggs that may have been released. The hormones can also sometimes affect the lining of the uterus so that if the egg is fertilized it will have a hard time attaching to the wall of the uterus.

Like other birth control methods that use hormones, such as the birth control pill or ring, a girl uses the birth control patch based on her monthly menstrual cycle. She puts on the patch on the first day of her menstrual cycle or the first Sunday after her menstrual cycle begins. She will change the patch on her skin once a week for 3 weeks in a row. (The patch should be applied to one of four areas: the abdomen, buttocks, upper arm, or upper torso — except for the breasts.) On the fourth week, no patch is worn, and a girl's period should start during this time.

Using The Patch

It's important to apply a new patch on the same day every week to ensure that it keeps working effectively. For example, a girl who applies her first patch on a Monday should always apply her patches on a Monday. When it's time to change the patch, pull the old one off first, before applying a new patch. Place the new patch on a different area from the old patch (but still on one of the four recommended areas listed above) to avoid skin irritation. Don't apply the patch to skin that is red, irritated, or cut.

For the first 7 days on the patch, use an additional form of contraception as well to prevent pregnancy.

If you forget to apply a new patch on the right day, or if the patch becomes loose and falls off, read the instructions that come in the package or call your doctor. If this happens you may need to use a backup method of birth control (such as condoms) or stop having sex for a while to protect against pregnancy. Also, if you stop using the patch for any reason, you will need to begin using another method of birth control, usually after 24 hours of removing your last patch.

It's OK to participate in normal activities like swimming and exercise while wearing the patch. You can also get it wet in the shower or in the bath. However, the patch should not be moved or removed until the week is up (pulling the patch off to reposition or move it may cause it to lose some of its stickiness and it might fall off easily). Don't try to decorate the patch, change the size of a patch by trimming it, or try to attach it with tape. Talk to your doctor if the patch falls off.

The patch should not be applied over makeup, creams, lotions, powder, or other skin products as these may prevent it from sticking well. (Skin products may also affect how hormones are absorbed by the skin.)

How Well Does It Work?

Ongoing studies suggest the birth control patch is as effective as the birth control pill. That means that about 8 out of 100 couples will have an unintended pregnancy during the first year of use. Of course, the chance of getting pregnant depends on whether you use the patch correctly. Delaying or missing a weekly application or removing a patch too early reduces its effectiveness and increases the chance a girl will become pregnant.

For girls who weigh more than 198 pounds (90 kilograms), the contraceptive patch may be less effective in preventing pregnancy.

In general, how well each type of birth control method works depends on a lot of things. These include whether a person has any health conditions or is taking any medications that might interfere with the patch. How effective the patch is at preventing pregnancy also depends on whether the method chosen is convenient — and whether the person remembers to use it correctly all the time.

Protection Against STDs

The birth control patch does not protect against sexually transmitted diseases (STDs). Couples having sex must always use condoms along with the birth control patch to protect against STDs.

Abstinence (the decision to not have sex) is the only method that always prevents pregnancy and STDs.

Possible Side Effects

The birth control patch is a safe and effective method of birth control. Most young women who use the patch have no side effects. Smoking cigarettes while using the patch can increase a girl's risk of certain side effects, which is why health professionals advise women who use the patch not to smoke.

The side effects that some women have while using the patch are similar to those experienced with the birth control pill. These may include:

• irregular menstrual bleeding
• nausea, headaches, dizziness, and breast tenderness
• mood changes
• blood clots (these are rare in women under 35 who do not smoke, but there may be a higher risk with the patch than with the Pill)

Other possible side effects seen in patch users include:

• skin reactions at the site of application of the patch
• problems with contact lens use — a change in vision or inability to wear the lenses
• menstrual cramps

Many of these side effects are mild and tend to disappear after 2 or 3 months.

Who Uses It?

The birth control patch may be a good choice for sexually active young women who weigh less than 198 pounds (90 kilograms) and find it difficult to remember to take a pill every day or who have difficulty swallowing pills.

Not all women can — or should — use the birth control patch. In some cases, medical or other conditions make the use of the patch less effective or more risky. For example, it is not recommended for women who have had blood clots, severe high blood pressure, certain types of cancers, certain types of migraine headaches, or diabetes with certain problems. It's recommended that girls who have had unexplained vaginal bleeding (bleeding that is not during their periods) or who suspect they may be pregnant should talk to their doctors, discontinue using the patch, and use another form of birth control in the meantime.

Girls who are interested in learning more about the possible health benefits and risks of different types of birth control, including the patch, should talk to a doctor or other health professional.

How Do You Get It?

A doctor or a nurse practitioner must prescribe the patch. He or she will ask questions about health and family medical history, and may also do a complete physical exam, including a blood pressure measurement and a pelvic exam. If recommending the patch, the doctor or nurse practitioner will write a prescription and provide instructions on how to use it.

Those who start using the patch may be asked to return within a few months for a blood pressure measurement and to ensure that there are no problems. After that, a doctor may recommend routine exams once or twice a year or as needed.

How Much Does It Cost?

The patch usually costs between $15 and $50 a month, although health and family planning clinics (such as Planned Parenthood) might sell them for less. In addition, the birth control patch and doctor's visits are covered by many health insurance plans.

Reviewed by: Larissa Hirsch, MD
Date reviewed: August 2009