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Definition

Contraception (birth control) prevents pregnancy by interfering with the normal process of ovulation, fertilization, and implantation. There are different kinds of birth control that act at different points in the process.

Purpose

Every month, a woman's body begins the process that can potentially lead to pregnancy. An egg (ovum) matures, the mucus that is secreted by the cervix (a cylindrical-shaped organ at the lower end of the uterus) changes to be more inviting to sperm, and the lining of the uterus grows in preparation for receiving a fertilized egg. Any woman who wants to prevent pregnancy must use a reliable form of birth control.

Types Of ContraceptivesEffectivenessPredicted (%)Actual (%)Birth control pills99.997Condoms9888Depo Provera99.799.7Diaphragm9482IUDs99.297Norplant99.799.7Tubal sterilization99.899.6Spermicides9779Vasectomy99.999.9

Birth control (contraception) is designed to interfere with the normal process and prevent the pregnancy that could result. There are different kinds of birth control that act at different points in the process, from ovulation, through fertilization, to implantation. Each method has its own side effects and risks. Some methods are more reliable than others.

There are more different types of birth control available today than ever. They can be divided into a few groups based on how they work. These groups include:

• Hormonal methods-These use medications (hormones) to prevent ovulation. Hormonal methods include birth control pills (oral contraceptives), Depo Provera injections, and Norplant.
• Barrier methods-These methods work by preventing the sperm from getting to and fertilizing the egg. Barrier methods include the condom, diaphragm, and cervical cap. The condom is the only form of birth control that also protects against sexually transmitted diseases, including HIV (the virus that causes AIDS).
• Spermicides-These medications kill sperm on contact. Most spermicides contain nonoxynyl-9. Spermicides come in many different forms such as jelly, foam, tablets, and even a transparent film. All are placed in the vagina. Spermicides work best when they are used at the same time as a barrier method.
• Intrauterine devices-Intrauterine contraceptive devices (IUDs) are inserted into the uterus, where they stay from one to 10 years. An IUD prevents the fertilized egg from implanting in the lining of the uterus, and may have other effects as well.
• Tubal sterilization-Tubal sterilization is a permanent form of contraception for women. Each fallopian tube is either tied or burned closed. The sperm cannot reach the egg, and the egg cannot travel to the uterus.
• Vasectomy-is the male form of sterilization, and should also be considered permanent. In vasectomy, the vas defrens, the tiny tubes that carry the sperm into the semen, are cut and tied off. Thus, no sperm can get into the semen.
• A newer and somewhat controversial form of birth control is emergency contraception. This type is used after unprotected intercourse and sometimes is referred to as the "morning-after pill".

Unfortunately, there is no perfect form of birth control. Only abstinence (not having sexual intercourse) can protect against unwanted pregnancy with 100% reliability. The failure rates, which means the rates of pregnancy, for most forms of birth control are quite low. However, some forms of birth control are more difficult or inconvenient to use than others. In actual practice, the birth control methods that are more difficult or inconvenient have much higher failure rates because they are not used regularly or as prescribed.

Description

Most forms of birth control have one thing in common. They are only effective if used faithfully. Birth control pills will work only if taken every day; the diaphragm is effective only if used during every episode of sexual intercourse. The same is true for condoms and the cervical cap. Some methods automatically work every day. These methods include Depo Provera, Norplant, the IUD, and tubal sterilization.

There are many different ways to use birth control. They can be divided into several groups:

• By mouth (oral)-Birth control pills must be taken by mouth every day.
• Injected-Depo Provera is a hormonal medication that is given by injection every three months.
• Implanted-Norplant is a long-acting hormonal form of birth control that is implanted under the skin of the upper arm.
• Vaginal-Spermicides and barrier methods work in the vagina.
• Intra-uterine-The IUD is inserted into the uterus.
• Surgical-Tubal sterilization is a form of surgery. A doctor must perform the procedure in a hospital or surgical clinic. Many women need general anesthesia.

The methods of birth control differ from each other in the timing of when they are used. Some methods of birth control must be used specifically at the time of sexual intercourse (condoms, diaphragm, cervical cap, spermicides). Emergency contraception must be started as soon as possible after intercourse and no more than 72 hours after. All other methods of birth control (hormonal methods, IUDs, tubal sterilization) must be working all the time to provide protection.

Precautions

There are risks associated with certain forms of birth control. Some of the risks of each method are listed below:

• Birth control pills-The hormone (estrogen) in birth control pills can increase the risk of heart attack in women over 35, particularly those who smoke. Certain women cannot use birth control pills.
• IUD-The IUD can increase the risk of serious pelvic infection. The IUD can also injure the uterus by poking into or through the uterine wall. Surgery might be needed to fix this.
• Tubal sterilization-"Tying the tubes" is a surgical procedure and has all the risks of any other surgery, including those associated with anesthesia, as well as infection and bleeding.
• Emergency contraceptive pills should not be used regularly for birth control. They can interrupt the menstrual cycle and are not 100% effective. If the emergency contraception fails, an ectopic pregnancy can occur.

Preparation

No specific preparation is needed before using contraception. However, a woman must be sure that she is not already pregnant before using a hormonal method or having an IUD placed.

Aftercare

No aftercare is needed.

Risks

Many methods of birth control have side effects. Knowing the side effects can help a woman to determine which method of birth control is right for her.

• Hormonal methods-The hormones in birth control pills, Depo Provera, and Norplant can cause changes in menstrual periods, changes in mood, weight gain, acne, and headaches. In addition, it may take many months to begin ovulating again once a woman stops using Depo Provera or Norplant.
• Barrier methods-A woman must insert the diaphragm in just the right way to be sure that it works properly. Some women get more urinary tract infections if they use a diaphragm. This is because the diaphragm can press against the urethra, the tube that connects the bladder to the outside.
• Spermicides-Some women and men are allergic to spermicides or find them irritating to the skin.
• IUD-The IUD is a foreign body that stays inside the uterus, and the uterus tries to get it out. A woman may have heavier menstrual periods and more menstrual cramping with an IUD in place.
• Tubal sterilization-Some women report increased menstrual discomfort after tubal ligation. It is not known if this is related to the tubal ligation itself.

There is no perfect form of birth control. Every method has a small failure rate and side effects. Some methods carry additional risks. However, every method of birth control can be effective if used properly.

Key Terms

Fallopian tubes

The thin tubes that connect the ovary to the uterus. Ova (eggs) travel from the ovary to the uterus. If the egg has been fertilized, it can implant in the uterus.

Fertilization

The joining of the sperm and the egg; conception.

Implantation

The process in which the fertilized egg embeds itself in the wall of the uterus.

Ovulation

The release of an egg (ovum) from the ovary.

For Your Information

Resources

Periodicals

• "Contraception; Overview." NWHRC Health Center - Contraception March 9, 2004.
• "Ectopic Pregnancy Is a Possibility When Emergency Contraception Fails." Health & Medicine Week March 15, 2004: 222.

This article was updated on 08-14-2006