Birth control is a way for men and women to prevent pregnancy. There are many different methods of birth control, including hormonal contraception such as “the pill.”

Women take the pill by mouth to prevent pregnancy, and, when taken correctly, it is up to 99.9% effective. However, the pill does not protect against sexually transmitted diseases, including HIV (the virus that causes AIDS). The latex male condom provides the best protection from most STDs. Other types of combined estrogen and progestin hormonal contraception include the patch and the vaginal ring.

How Does Hormonal Contraception Work?

A woman becomes pregnant when an egg released from her ovary (the organ that holds her eggs) is fertilized by a man’s sperm. The fertilized egg attaches to the inside of a woman’s womb (uterus), where it receives nourishment and develops into a baby. Hormones in the woman’s body control the release of the egg from the ovary — called ovulation — and prepare the body to accept the fertilized egg.

Hormonal contraceptives (the pill, the patch, and the vaginal ring) all contain a small amount of man-made estrogen and progestin hormones. These hormones work to inhibit the body’s natural cyclical hormones to prevent pregnancy. Pregnancy is prevented by a combination of factors. The hormonal contraceptive usually stops the body from ovulating. Hormonal contraceptives also change the cervical mucus to make it difficult for the sperm to go through the cervix and find an egg. Hormonal contraceptives can also prevent pregnancy by changing the lining of the womb so it’s unlikely the fertilized egg will be implanted.

Another option for hormonal contraceptives is the extended-cycle pill, such as Seasonale, which was the first one to be approved. Seasonale contains the same hormones as other birth control pills, but the hormones are taken in a longer cycle. That reduces the number of menstrual periods from 13 periods a year to only four a year. That means a woman who takes this pill will menstruate only once each season.

Seasonale contains the same combination of two hormones that are commonly used in other hormonal contraceptives. But the pill is taken continuously for 12 weeks followed by one week of inactive pills, which results in a menstrual cycle. Other extended-cycle pills, such as Seasonique and LoSeasonique use a different configuration of the same hormones. Both of these pills use estrogen in the final week, with LoSeasonique providing a lower dose option.

What Are Mini Pills?

These are pills that contain only one hormone (progestin). They do not contain estrogen and may be prescribed in women who are breastfeeding or in women who experience nausea or other side effects of estrogen.

How Do Mini Pills Work?

Mini pills work by thickening the cervical mucus so the sperm cannot reach the egg. The hormone in the pills also changes the lining of the uterus, so that implantation of a fertilized egg is much less likely to occur. In some cases, mini pills prevent the release of an egg. A pill is taken every day.

How Effective Are Mini Pills?

If mini pills are used consistently and correctly, they are about 95% effective — somewhat less effective than standard birth control pills.

How Are Birth Control Pills Packaged?

You will receive a set of pills packaged in a thin case. Pill packs containing regular birth control pills have either 21 or 28 pills. Twenty-one-day pill packs contain 21 active pills. Twenty-eight day pill packs contain 21 active pills and seven inactive (placebo) pills. The pill packs are marked with the days of the week to remind you to take a pill every day. The seven inactive pills in the 28-day pill pack are added so that you are reminded to start a new pill pack after 28 days.

Some newer pills have only 2 inactive pills or even no inactive pills in the pack. It’s important to always take all the pills to be sure you are protected from getting pregnant.

A package of extended-cycle Seasonale contains 84 active pink tablets and seven inactive white pills. With Seasonique and LoSeasonique, the last 7 pills contain estrogen only.

How Do I Begin Birth Control Pills?

Ask your doctor when you should start birth control pills. If you are still having your period on the day that you have been told to start your pill pack, go ahead and start the pill pack anyway. You will get your next period about 25 days after starting the pill pack.

It’s best to take the pills at the same time every day. You can take the pill at anytime during the day, but taking it either before breakfast or at bedtime will help make it easier to remember.

Extended-cycle pills works in a similar way. You start taking the pill the first Sunday after your period starts. If your period starts on a Sunday, start Seasonale that day. Then you take one active tablet a day for 84 consecutive days. Then depending on the type of pill you’re taking, you have seven days of taking one placebo or estrogen only pill per day.

When Do I Start Another Birth Control Pill Pack?

You will start each new birth control pill pack on the same day of the week that you initially started it. If you are on the 21-day pill pack, start the new pill pack seven days after you finished the old pill pack. If you are on the 28-day pill pack, begin the new pack after taking the last pill in the old pack.

Start your new pill pack on schedule whether or not you get your period or are still having your period.

How Soon Do Birth Control Pills Work?

When taken as directed, birth control pills are usually effective the first month you begin taking them. To be safe, some doctors recommend the use of another form of birth control, such as condoms and foam, during the first month. After the first month, you can just rely on the pill for birth control.

What If I Forget to Take a Birth Control Pill?

If you forget to take a birth control pill, take it as soon as you remember. If you don’t remember until the next day, go ahead and take two pills that day. If you forget to take your pills for two days, take two pills the day you remember and two pills the next day. You will then be back on schedule. If you miss more than two pills, call your doctor. You may be told to take one pill daily until Sunday then start a new pill pack or to discard the rest of the pill pack and start over with a new pack that same day.

Any time you forget to take a pill, you must use another form of birth control until you finish the pill pack. When you forget to take a pill, you increase the chance of releasing an egg from your ovary. If you miss your period and have forgotten to take one or more active pills, get a pregnancy test. If you miss two periods even though you have taken all your pills on schedule, you should get a pregnancy test.

With some pills you may not have a period. Talk with your doctor before you start taking your pills about what to expect, and then follow your doctor’s instructions about what to do if you don’t have a period.

It is very important to take the mini pills (progestin only) at the exact same time each day. If you miss a pill or are more than three hours late for a pill you should take the pill as soon as you remember and use a backup method (such as a condom or spermicide) for the next 48 hours.

Are There Side Effects of Birth Control Pills?

Yes, there are side effects of birth control pills, although the majority are not serious. Side effects include:

• Nausea
• Sore or swollen breasts
• Small amounts of blood, or spotting, between periods
• Lighter periods
• Mood changes
• Headache (mild)

The following side effects, easily remembered by the word “ACHES,” are less common but more serious. If you experience any of these, contact your doctor immediately. If you cannot reach your doctor, go to an emergency room or urgent care center for evaluation. These symptoms may indicate a serious disorder, such as liver disease, gallbladder disease, stroke, blood clots, high blood pressure, or heart disease. They include:

• Abdominal pain (stomach pain)
• Chest pain
• Headaches (severe)
• Eye problems (blurred vision)
• Swelling or aching in the legs and thighs

Birth control pills that contain drospirenone, including YAZ and Yasmin, have been investigated by the FDA because of the possibility that they may cause an increased risk for blood clots. Drospirenone is a man-made version of the hormone progesterone. Other brands containing drospirenone include Beyaz, Safyral, Gianvi, Loryna, Ocella, Syeda, and Zarah.

The results of the investigation are inconsistent. Some studies showed there was an increased risk while other studies showed no increased risk. The drugs are still available. A summary of the findings is contained on the packaging label. If you are taking a pill with drospirenone, talk with your doctor about your risk.

The pill is not associated with an overall increased risk of cancer. Its use was associated with a reduced risk of colorectal, endometrial, and ovarian cancer. An increased risk of breast and cervical cancer was observed in current and recent birth control pill users, but the risk disappeared within five years.

Can Any Woman Take Birth Control Pills?

Birth control pills can be taken safely by most women. They are not recommended, though, for women over age 35 who smoke. If you don’t smoke, you can use hormonal contraceptives until menopause. In addition, you should not take hormonal contraceptives if you have had:

• Blood clots in the arms, legs, or lungs
• Serious heart or liver disease
• Cancer of the breast or uterus
• Uncontrolled high blood pressure
• Migraines with aura

There are other conditions as well that may increase your level of risk that comes with taking birth control pills. If you are not sure if you are affected by one of these conditions, ask your doctor. Also, inform your doctor if you have a first-degree relative (parent, brother, sister, child) who has had blood clots in the legs or lungs.

Is it OK to Take Other Drugs While Taking Birth Control Pills?

Some drugs, including antibiotics and antiseizure meds, can reduce the effectiveness of birth control pills. Tell your doctor about all of the medications and over-the-counter agents (including herbs) that you take.

Points to Keep in Mind When Taking Birth Control Pills

• Keep another form of birth control, like spermicidal foam and condoms, on hand in case you forget to take a pill.
• Carry your pills with you if you don’t always sleep at the same place.
• Take your pill at the same time every day. If you are using the patch, replace your patch weekly on the same day. If you are using the vaginal ring, remove it after three weeks of use and insert a new one 7 days later.

• Get your refills soon after you start the last prescription. Don’t wait until the last minute to request refills.
• Birth control pills, patches, and vaginal rings are all medications. Always tell your doctor or pharmacist you are on the pill, patch, or vaginal ring if you see him or her for any reason.