About half of all pregnancies in this country are unplanned, according to the American College of Obstetricians and Gynecologists. For a woman who wants to plan when she becomes pregnant, however, there are many choices.
Contraception--also called birth control--refers to methods or devices that prevent pregnancy either by preventing a woman’s egg from being fertilized by sperm or by preventing a fertilized egg from being implanted in the uterus.
Which method or methods you choose depends on several factors, including your menstrual cycle, any existing health conditions, convenience of the contraceptive and its ease of use, risk factors, side effects, and cost. Your health care provider can help you determine the method that's appropriate for you.
Keep in mind that you may change your contraception method as the circumstances of your life change. When choosing a method, you should consider how often you have sex, if you are in a monogamous relationship, if you are willing to plan for sex or want a method that doesn't depend on planning, and how willing you are to track your fertile days or take a pill every day. To work effectively, a contraceptive method must be used correctly and consistently.
Below is a general description of the most common categories of contraception methods approved by the FDA.
These methods, available only by prescription, use synthetic hormones similar to estrogen and progesterone, the hormones naturally produced by a woman’s body. The hormones prevent ovulation--when the ovaries release an egg. Hormonal methods offer continuous contraception, but they do not protect you against sexually transmitted infections (STIs) and condoms should be used. Women who have had a stroke, have liver disease, breast cancer, or problems with blood clotting should not use hormonal contraceptives. If you are over age 35 and smoke, your health care provider may advise against these methods.
Birth control pills/oral contraceptives
Combination birth control pills contain both estrogen and progestin, a synthetic form of the hormone progesterone; others have only progestin (progestin-only mini-pill). A chewable form of the combination pill is available:
Combination pills prevent ovulation. These pills are taken daily, regardless of how often a woman has intercourse. Women using the chewable tablet must drink eight ounces of liquid immediately after taking it. The usual method of taking birth control pills allows a woman to have a predictable period every four weeks. Some women may be able to use combination pills on a schedule that instead allows them to have a menstrual period every 13 weeks. This must be under the direction of a health care provider, however. The CDC says these pills are 92 to 99 percent effective when prescribed and taken correctly. Possible side effects of the combination pill include dizziness, nausea, and changes in menstruation, mood or weight. Rarely, cardiovascular disease can result; this can include high blood pressure, blood clots, heart attack, and strokes. Women who smoke and are older than age 35 should not use these pills.
Progestin-only pills prevent pregnancy by thickening cervical mucus to stop the sperm from reaching the egg. The CDC says these pills are 92 to 99 percent effective when prescribed and taken correctly. They must be taken on a daily schedule, regardless of how often a woman has intercourse. Possible side effects of the progestin-only pill include irregular bleeding, weight gain, and breast tenderness. Women should take these pills at the same time every day. Missing pills or taking them irregularly can lower the effectiveness of this form of birth control and increase the chances for becoming pregnant.
This is a skin patch that releases estrogen and progestin directly into the bloodstream. It is worn on the lower abdomen, buttocks or upper body, but not on the breasts. A new patch is applied once a week for three weeks. It is not worn during the fourth week to allow a menstrual period. The CDC says it is 92 percent effective, but it may be less effective in women who weigh more than 198 pounds. Patches contain more estrogen than birth control pills do. Possible side effects are similar to those of the combination oral contraceptive pill, but the risk for blood clots may be greater with the patch because it contains more estrogen. Other factors that put women at risk for blood clots are smoking, obesity, inactivity, and surgery; using the patch with these risks increases them.
Vaginal contraceptive ring (NuvaRing)
This is a flexible ring about two inches in diameter that is inserted by a woman into her vagina. There, it releases progestin and estrogen. The ring remains in place for three weeks, and is then removed for one week to allow a menstrual period. The CDC says it is 92 percent effective when used correctly. If the ring is expelled from the vagina and remains out for three or more hours, another method of birth control must be used until a new ring has been in place for seven days. Possible side effects include vaginal discharge, vaginitis, irritation, and side effects similar to those of the combination oral contraceptive pill.
Women over age 35 who are obese or smoke should not use the vaginal ring.
Two types of hormone injections are available:
Depot medroxyprogesterone acetate (DMPA) is a form of the hormone progestin. Injected once every three months, it prevents pregnancy in three ways: It prevents ovulation, stops the sperm from reaching the egg, and prevents the fertilized egg from implanting in the uterus. The CDC says it is 92 to 99 percent effective. Most women have irregular bleeding during the first few months of DMPA use. With long-term use of a year or more, a woman may stop having menstrual periods. Periods resume when a woman stops using this contraceptive. Possible side effects include irregular bleeding, weight gain, breast tenderness, and headaches.
Currently, only one form of implantable contraception is available, Implanon, and its newer version, Nexplanon. These contraceptives consist of a small sticklike rod placed beneath the skin of the inner upper arm. The rod slowly releases etonogestrel, another type of progestin. Nexplanon is radio-opaque, meaning that the rod can be detected on X-ray. Effective for three years, Implanon or Nexplanon must be inserted and removed by a health care provider using a minor outpatient surgical procedure. In addition to pain or irritation for a few days at the site of injection, possible side effects include irregular, missed or painful periods, weight gain, acne, headaches, breast tenderness, hair loss, changes in mood and/or libido, abdominal pain, and an increase in blood pressure. It is important to have regular follow-up appointments with your health care provider.
Intrauterine device (IUD)
An IUD is a T-shaped plastic frame with thread attached that is inserted into the uterus by a health care provider. IUDs, which offer continuous contraception, come in two types. One type, ParaGuard, has copper on the plastic frame; another type, Mirena, contains a synthetic form of the hormone progesterone called levonorgestrel. An IUD works by releasing copper or progestin to change the cervical mucus and prevent sperm from entering the fallopian tubes, the places where eggs are fertilized. If a sperm does reach an egg, an IUD prevents the fertilized egg from implanting in the uterus. IUDs are 98 to 99 percent effective. After insertion, the copper IUD can remain in place up to 10 years, and the Mirena IUD for five years. All IUDs must be removed by a health care provider. IUDs do not protect you from STIs. Possible side effects include cramps, bleeding, pelvic inflammatory disease, infertility, and perforation of the uterus.
Barrier devices come in many forms. Unlike hormonal methods or the IUD, which work continuously to provide protection against pregnancy, a barrier device is used only when a woman has intercourse. A plus is that barrier devices are usually cheaper. A drawback is the need to plan for sex so that you have a barrier device with you. The diaphragm, cervical cap and shield may be difficult for some women to insert properly. Some barrier methods can help protect you against STIs.
The female condom is a lubricated, loose-fitting polyurethane pouch that is inserted into the vagina. It surrounds the penis during intercourse and serves as a lining to physically protect the vagina and cervix from infections and trap sperm to prevent pregnancy. Available over the counter (OTC), the condom has a closed end and an open end, with flexible rings at both ends. The closed end is inserted into the vagina, and the ring holds it in place over the cervix. The female condom can be inserted up to 24 hours before intercourse, and can only be used once. Although it comes with lubrication, more may be needed during intercourse. The female condom is stronger than a male condom and should never be used with a male condom. It is between 80 and 95 percent effective in preventing pregnancy and may protect from fluid-transmitted and some virally transmitted STIs.
The male condom is a lubricated sheath that is put on an erect penis prior to entry into the vagina. The male condom traps sperm and forms a physical barrier between the vagina and penis. Because of the barrier, it offers protection from fluid-transmitted and some virally transmitted STIs. Available OTC, most male condoms are made of latex which protects from STIs. Some condoms are made from polyurethane, silicone, and other synthetic materials. Condoms made from animal membrane contain small pores, which may allow passage of viruses, do not protect from you from STIs, and should not be used. Male condoms come in different sizes; a correct size is important to assure protection. When the condom is on the erect penis, there should be room at the tip to allow sperm and fluids. If more lubrication is needed, use only water-based lubricants with latex condoms. A male condom can only be used once. After intercourse, the male should withdraw the penis while holding onto the base of the condom to prevent it from coming off. Used correctly, male condoms are 85 to 98 percent effective in preventing pregnancy. Using a vaginal spermicide with a condom increases its effectiveness. Using a condom that is too old (past its expiration date), brittle, torn or damaged, or put on incorrectly will not protect you from pregnancy or infections.
Diaphragm and cervical cap
These reusable barrier methods of birth control block sperm from entering the cervix and reaching the egg. They are made of latex, and all require a prescription. The diaphragm is a shallow cup; the cap is smaller and thimble-shaped with a strap to aid removal. The diaphragm and cap come in various sizes; a health care provider determines what size you need. Having a child or gaining or losing a significant amount of weight can affect how these fit and may mean you need a different size. Both methods are used with a spermicide to kill sperm. When used correctly, the cervical cap is 80 to 91 percent effective in preventing pregnancy, and the diaphragm is 83 to 94 percent effective. All must be inserted before sex and be left in place for six to eight hours after sex. The diaphragm must be removed by 24 hours after intercourse to avoid the risk for toxic shock syndrome; the cap must be removed 48 hours after intercourse, also to avoid the risk for toxic shock. Other possible side effects of the cap include urinary tract and vaginal infections. The diaphragm, when used with a spermicide, can protect against some STIs. The cap does not provide much protection against STIs.
This barrier method of birth control is a soft, disk-shaped device with a loop for removal. Available OTC, it is made of polyurethane foam and contains the spermicide nonoxynol-9. Prior to intercourse, the sponge is moistened with water and inserted so that the dimpled side covers the cervix. It can be put in up to 24 hours before sex. It must be left in for at least six hours after intercourse. It is 84 to 91 percent effective, if used correctly. It is effective for more than one act of intercourse for up to 24 hours. It must be removed within 30 hours of being inserted. If left in longer, there is a risk of getting toxic shock syndrome. The sponge does not protect against STIs.
Emergency contraception keeps a woman from becoming pregnant. If a woman is already pregnant, emergency contraception will not work. These are the circumstances in which emergency contraception methods can be used:
A contraceptive method fails, such a condom breaking or coming off during sex
No contraception was used when you had sex
You were forced to have sex
You missed two or more birth control pills in a row
You were late getting your DMPA shot
Emergency contraception works by preventing the egg from leaving the ovary, by preventing the egg from being fertilized, or by preventing a fertilized egg from implanting in the uterus. It does not affect a woman’s future pregnancies. If you think you might need emergency contraception in the future, you can talk with your health care provider about getting emergency contraceptive pills (ECPs) at your next regular exam.
If you do not have a menstrual period three weeks after you take ECPs, or if you think you might be pregnant after taking ECPs, get a pregnancy test to make sure you're not pregnant.
Types of emergency contraception
There are two types of emergency contraception, often called morning-after or day-after pills: two pills containing only progestin or a combination of birth control pills.
Several types of a progestin-only pill, which is sometimes called Plan B, are available as an over-the-counter option for women ages 17 and older; it is available for girls under 17 only by prescription. This treatment contains the progestin levonorgestrel, which is found in prescription birth control pills but in a lower dose. Depending on the type of pill, one or two pills are taken, either together or one within three days after unprotected sex and the second 12 hours later. When used as directed, these pills effectively and safely prevent pregnancy 88 to 95 percent of the time. They are most effective when taken within 24 hours of unprotected sex. A new form of emergency contraception pill recently approved by the FDA, called ella, contains and antiprogestin, that is effective even when taken up to five days after unprotected sex. Possible side effects include nausea, vomiting, abdominal pain, fatigue and headache. Taking both pills at the same time will not increase your chances of having these side effects.
Combined pills are high-doses of birth control pills containing both estrogen and and can be used as emergency contraception. Different brands of combined birth control pills have different doses of these hormones, and the number of pills in a dose is different for each brand. Not all brands can be used for emergency contraception. For more information on birth control pills that can be used for emergency contraception, go to Not-2-late.com.
In general, the pills are taken in two doses, one dose right away and the second dose 12 hours later. Always use the same brand for both doses. Combined estrogen and progestin pills are 75 to 80 percent effective when taken this way. Some women feel sick and throw up after taking them. If you throw up within one hour after taking emergency contraception pills, call your doctor or pharmacist as you may need to repeat the dose. Emergency contraception pills should not be used as a routine form of contraception and do not protect against sexually transmitted infections.
A copper IUD inserted within seven days of unprotected sex can prevent 99 percent of pregnancies. It can prevent the sperm from fertilizing the egg or prevent a fertilized egg from implanting in the uterus. It can remain in place and be used as a method of birth control, or it can be removed after the next normal menstrual period.
The abortion pill mifepristone (also called RU-486) is not used for contraception. It works after a woman becomes pregnant, when a fertilized egg has attached to the uterus. Mifepristone is a synthetic steroid that blocks progesterone, the hormone necessary to maintain pregnancy. When progesterone is not available, the fertilized egg cannot stay attached to the uterus.
Mifepristone is available only by prescription. Before prescribing mifepristone, a health care provider must do an HCG blood test and an ultrasound to confirm that a woman is pregnant, that she does not have an ectopic (tubal) pregnancy, and the gestational week of the pregnancy. Mifepristone is approved for use up to the 49th day of pregnancy, or about seven weeks. When the pregnancy and date of pregnancy are confirmed, a woman takes one dose of mifepristone. Two days later, she takes a second drug, misoprostol, which causes the uterus to contract. Within six days to one week, the pregnancy is terminated.
A woman must return to her health care provider’s office to confirm that the pregnancy was terminated. If it was not, a surgical abortion must be performed. Mifepristone is 92 percent effective in ending a pregnancy, if taken during the first seven weeks of pregnancy. Possible side effects of mifepristone include uterine cramps, fatigue, nausea, and heavy bleeding.
Below is a summary of the various types of contraceptives, their effectiveness in preventing pregnancy, side effects, and whether they provide protection against sexually transmitted infections.
Possible side effects
Protection against STIs
Dizziness, nausea, menstrual or mood changes, weight gain
Dizziness, nausea, menstrual or mood changes, weight gain, blood clots
Vaginal discharge, vaginitis, dizziness, nausea, menstrual or mood changes, weight gain
Irregular bleeding, weight gain, breast tenderness, headaches
Irregular (or missing) periods, weight gain, acne, headaches, breast tenderness, hair loss, changes in mood and/or libido, abdominal pain, increase in blood pressure
Cramps, bleeding, pelvic inflammatory disease, infertility, perforation of uterus
Diaphragm and cap
Toxic shock, if left in for too long
Diaphragm provides some protection; cap does not
Toxic shock, if left in for too long
Complications of surgery