Which form of birth control you choose depends on a number of different factors, including your health, how often you have sex, and whether or not you want children.

Here are some factors to consider when selecting a birth control method:

• Effectiveness -- How well does the method prevent pregnancy? Look at the number of pregnancies in 100 women using that method over a period of one year. If an unplanned pregnancy would be viewed as potentially devastating to the individual or couple, a highly effective method should be chosen. In contrast, if a couple is simply trying to postpone pregnancy, but feels that a pregnancy could be welcomed if it occurred earlier than planned, a less effective method may be a reasonable choice.
• Cost -- is the method affordable?
• Health risk -- What are the potential health risks? For example, birth control pills are usually not recommended for women over age 35 who also smoke.
• Partner involvement -- The willingness of a partner to accept and support a given method may affect your choice of birth control. However, you also may want to re-consider a sexual relationship with a partner unwilling to take an active and supportive role.
• Permanence -- Do you want a temporary (and generally less effective) method, or a long-term or even permanent (and more effective) method?
• Preventing HIV and sexually transmitted diseases (STDs) -- Many methods offer no protection against STDs. In general, condoms are the best choice for preventing STDs, especially when combined with spermicides.
• Availability -- Can the method be used without a prescription, provider visit, or, in the case of minors, parental consent?

CONDOMS

• A condom is a thin latex or polyurethane sheath. The male condom is placed around the erect penis. The female condom is placed inside the vagina before intercourse. Semen collects inside the condom, which must be carefully removed after intercourse.
• A condom must be worn at all times during intercourse to prevent pregnancy.
• Condoms are available in most drug and grocery stores. Some family planning clinics offer free condoms.
• Latex condoms help prevent HIV and other STDs. Polyurethane condoms may give some protection against STDs, but they are not as effective as latex ones.
• About 14 pregnancies occur over 1 year out of 100 couples using male condoms, and about 21 pregnancies occur over 1 year out of 100 couples using female condoms. They are more effective when spermicide is also used.
• Risks include irritation and allergic reactions, particularly to latex.
• Condoms are used only once.

SPERMICIDES

• Spermicides are chemical jellies, foams, creams, or suppositories that kill sperm.
• They can be purchased in most drug and grocery stores.
• This method used by itself is not very effective. About 26 pregnancies occur over 1 year out of 100 women using this method alone.
• Spermicides are generally combined with other methods (such as condoms or diaphragm) as extra protection.
• Warning: The spermicide nonoxynol-9 can help prevent pregnancy, but also may increase the risk of HIV transmission.
• Risks include irritation and allergic reactions.

DIAPHRAGM AND CERVICAL CAP

• A diaphragm is a flexible rubber cup that is filled with spermicidal cream or jelly.
• It is placed into the vagina over the cervix, before intercourse, to prevent sperm from reaching the uterus.
• It should be left in place for 6 to 8 hours after intercourse.
• Diaphragms must be prescribed by a woman's health care provider, who determines the correct type and size of diaphragm for the woman.
• About 5-20 pregnancies occur over 1 year in 100 women using this method, depending on proper use.
• A similar, smaller device is called a cervical cap.
• Risks include irritation and allergic reactions to the diaphragm or spermicide, and urinary tract infection. In rare cases, toxic shock syndrome may develop in women who leave the diaphragm in too long. A cervical cap may cause an abnormal Pap test.

VAGINAL SPONGE

• Vaginal contraceptive sponges are soft synthetic sponges saturated with a spermicide. Prior to intercourse, the sponge is moistened, inserted into the vagina, and placed over the cervix. After intercourse, the sponge is left in place for 6 to 8 hours.
• It is quite similar to the diaphragm as a barrier mechanism, but you do not need to be fitted by your doctor. The sponge can be purchased over the counter.
• In April 2005, the FDA granted re-approval for the Today sponge to return to the U.S. market.
• About 18 to 28 pregnancies occur over one year for every 100 women using this method.
• The sponge may be more effective in women who have not previously delivered a baby.
• Risks include irritation, allergic reaction, trouble removing the sponge. In rare cases, toxic shock syndrome may occur.

COMBINATION BIRTH CONTROL PILLS

• Also called oral contraceptives or just the "pill", this method combines the hormones estrogen and progestin to prevent ovulation.
• A health care provider must prescribe birth control pills.
• The method is highly effective if the woman remembers to take her pill consistently each day.
• Women who experience unpleasant side effects on one type of pill are usually able to adjust to a different type.
• About 2 to 3 pregnancies occur over 1 year out of 100 women who never miss a pill.
• Birth control pills may decrease a woman's risk for ovarian cancer.
• Birth controll pills may cause a number of side effects, including dizziness, irregular menstrual cycles, nausea, mood changes, and weight gain. In rare cases, they can lead to high blood pressure, blood clots, heart attack, and stroke.

THE MINI-PILL

• The "mini-pill" is a type of birth control pill that contains only progestin, no estrogen.
• It is an alternative for women who are sensitive to estrogen or cannot take estrogen for other reasons.
• The effectiveness of progestin-only oral contraceptives is slightly less than that of the combination type. About 3 pregnancies occur over a 1 year period in 100 women using this method.
• Risks include irregular bleeding, weight gain, and breast tenderness.

THREE-MONTH PILL (SEASONALE)

• In 2003, the FDA-approved an estrogen and progestin pill called Seasonale. It is taken for three straight months, followed by one week of inactive pills.
• A women gets her period about four times a year, during the 13th week of her cycle.
• Seasonale is available by prescription.
• Fewer than 2 out of 100 women per year get pregnant using this method.
• The risks are similar to other birth control pills. Some women may have more spotting between periods.
• The pills must be taken daily, preferably at the same time of day.

PROGESTIN IMPLANTS

• Implants are small rods implanted surgically beneath the skin, usually on the upper arm. The rods release a continuous dose of progestin to prevent ovulation.
• Implants work for 5 years. The initial cost is generally higher than some other methods, but the overall cost may be less over the 5-year period.
• The Norplant implant has been removed from the U.S. market. A similar implanted rod system, Implanon, is available. It works for 3 years.
• Less than 1 pregnancy occurs over 1 year out of 100 women using this type of contraception.

HORMONE INJECTIONS

• Progestin injections, such as Depo-Provera, are given into the muscles of the upper arm or buttocks. This injection prevents ovulation.
• A single shot works for up to 90 days.
• Less than 1 pregnancy occurs over 1 year in 100 women using this method.
• Sometimes the effect of this medication lasts longer than 90 days. If you are planning to become pregnant in the near future, you might consider a different method.

SKIN PATCH

• The skin patch (Ortho Evra) is placed on your shoulder, buttocks, or other convenient location. It continually releases progestin and estrogen. Like other hormone methods, a prescription is required.
• The patch provides weekly protection. A new patch is applied each week for three weeks, followed by one week without a patch.
• About 1 pregnancy occurs over 1 year out of 100 women using this method.
• Estrogen levels are higher with the patch than with birth control pills. In theory, higher estrogen levels may increase your risk of blood clots.

VAGINAL RING

• The vaginal ring (NuvaRing) is a flexible ring about 2 inches wide that is placed into the vagina. It releases the hormones progestin and estrogen.
• A prescription is required.
• The woman inserts it herself. It stays in the vagina for 3 weeks. At the end of the third week, the woman takes the ring out for 1 week. The ring should not be removed until the end of the 3 weeks.
• About 1 pregnancy occurs over 1 year out of 100 women using this method.
• Side effects (nausea, breast tenderness) are less severe than those caused by birth control pills or patches.
• Risks include vaginal discharge and vaginitis, as well as those similar to the combined birth control pill.

IUD

• The IUD is a small plastic or copper device placed inside the woman's uterus by her health care provider. Some IUDs release small amounts of progestin. IUDs may be left in place for 5 - 10 years, depending on the device used
• IUDs can be placed at almost any time.
• IUDs are safe and work well. Fewer than 1 out of 100 women per year will get pregnant using an IUD.
• Risks and complications include cramps, bleeding (sometimes severe), and perforation of the uterus.

NATURAL FAMILY PLANNING

• This method involves observing certain body changes in the woman (for example, changes in cervical mucus and basal body temperature) and recording them on a calendar to determine when ovulation occurs. The couple abstains from unprotected sex for several days before and after the day ovulation is believed to occur.
• This method requires education and training in recognizing the body's changes, as well as a great deal of continuous and committed effort.
• About 15 to 20 pregnancies occur over 1 year out of 100 women using this method (for those who are properly trained).

TUBAL LIGATION

• During tubal ligation, a woman's fallopian tubes are cut, sealed, or blocked by a special clip, preventing eggs and sperm from entering the tubes. It is usually performed immediately after childbirth, or by laparoscopic surgery.
• Tubal ligations are best for women and couples who believe they never wish to have children in the future. While viewed as a permanent method, the operation can sometimes be reversed if a woman later chooses to become pregnant.

VASECTOMY

• A vasectomy is a simple, permanent procedure for men. The vas deferens (the tubes that carry sperm) are cut and sealed.
• A vasectomy is performed safely in a doctor’s office using a local anesthetic to numb the area.
• Vasectomies are best for men and couples who believe they never wish to have children in the future. While often viewed as a permanent method, they can sometimes be reversed.

EMERGENCY ("MORNING AFTER") BIRTH CONTROL

• The "morning after" pill consists of two doses of hormone pills taken as soon as possible within 72 hours after unprotected intercourse.
• The pill is available without a prescription for purchase by anyone 18 years and older.
• The pill may prevent pregnancy by temporarily blocking eggs from being produced, by stopping fertilization, or keeping a fertilized egg from becoming implanted in the uterus.
• The morning after pill may be appropriate in cases of rape; having a condom break or slip off during sex; missing two or more birth control pills during a monthly cycle; and having unplanned sex.
• Risks include nausea, vomiting, abdominal pain, fatigue, and headache.

UNRELIABLE METHODS

• Coitus interruptus is the withdrawal of the penis from the vagina prior to ejaculation. Some semen frequently escapes prior to full withdrawal, enough to cause a pregnancy.
• Douching shortly after sex is ineffective because sperm can make their way past the cervix within 90 seconds after ejaculation.
• Breastfeeding. Despite the myths, women who are breastfeeding can become pregnant.

CALL YOUR HEALTH CARE PROVIDER IF:

• You would like to further information about birth control options
• You want to start using a specific method of birth control that requires a prescription or needs to be inserted by a health care provider
• You have had unprotected intercourse or method failure (for example, a broken condom) within the past 72 hours, and you do not want to become pregnant

MacIsaac L.Intrauterine contraception: the pendulum swings back. Obstet Gynecol Clin North Am. 2007 March;34(1):91-111, ix.

Mishell DR. Family planning: contraception, sterilization, and pregnancy termination. In: Katz VL, Lentz GM, Lobo RA, Gershenson DM, eds. Comprehensive Gynecology. 5th ed. Philadelphia, Pa: Mosby Elsevier; 2007:chap 14.

US Food and Drug Administration. Birth Control Guide. Rockville, MD: FDA Office of Public Affairs; December 2003.