Contraception

Contraception 

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.

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:

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:

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:

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.

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.

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.

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.

---

contraception /con·tra·cep·tion/ (-sep´shun) the prevention of conception or impregnation.

---

con·tra·cep·tion (kntr-spshn)

n.

Intentional prevention of conception or impregnation through the use of various devices, agents, drugs, sexual practices, or surgical procedures.

---

contraception,

n a process or technique for the prevention of pregnancy by means of a medication, device, or method that blocks or alters one or more of the processes of reproduction in such a way that sexual union can occur without impregnation.

---

contraception

prevention of conception or impregnation. Little practiced in the animal world (except in dogs and cats), population control being effected by other means. Is used in some less-developed communities where cattle are used as draft animals.

---

immunological contraception

involves immune-mediated control of hormone or degeneration of reproductive tissues. Some methods investigated in dogs include immunization with bovine or ovine luteinizing hormone (LH) or gonadotropin so that cross-reacting antibodies neutralize the animal's own hormone. Antibodies to porcine zona pellucida antigens inhibit fertilization and implantation.