Birth control refers to the practice of deliberately controlling the number of children born, especially by reducing or eliminating the possibility of conception. While there are many forms of birth control, they can be broadly classified as follows: behavioral methods; surgical methods; barrier methods; hormonal methods; and methods that prevent the continuation of pregnancy, namely abortion.
Behavioral methods include the practice of abstinence from intercourse, particularly during the fertile period of the woman's menstrual cycle, commonly known as the rhythm method. While the fertile days generally occur in the three to four days before and after ovulation, this particular method of birth control is frequently ineffective because of the difficulty in predicting ovulation with the necessary accuracy. Other behavioral methods include withdrawal of the penis from the vagina prior to male orgasm. This depends on complete and timely withdrawal, with no sperm deposited anywhere near the vulva . It is not an effective method of birth control.
Surgical methods of birth control can be used by both males and females. In males, this involves a vasectomy in which the vas deferens is severed. In females, a tubal ligation ties off the fallopian tubes , thus preventing sperm from reaching the egg. These methods offer a high degree of effectiveness but have the disadvantage of being difficult to reverse should the individuals ever want to regain fertility.
Barrier methods of birth control involve preventing the sperm from reaching and fertilizing the egg. For males, this entails the use of condoms to prevent the sperm from entering the vagina. In females, sponges, spermicides, or diaphragms are used to prevent the sperm from entering the uterus and ultimately the fallopian tubes. When used in combination and consistently, these methods can be highly effective, but they frequently fail due to inconsistent usage or failure of the barrier (for example, a broken condom or improperly inserted diaphragm).
Hormonal methods are among the most common and effective means of birth control worldwide. These methods rely on the use of hormones (usually a combination of progesterone and estrogen) that disrupt the normal menstrual cycle in the female, resulting in a suppression of ovulation and hence conception. While the birth control pill is the most common of these methods, other common hormonal methods of birth control are implants (such as Norplant) that release hormone continuously or injections of hormones every few months that likewise suppress ovulation.
All of these hormonal methods are highly effective means of birth control with generally minor side effects. Major side effects, such as stroke, are rare and generally associated with increasing female age and smoking. The "morning after" pill is also hormonal in nature. It is often referred to as an "emergency form" of birth control, and is taken following intercourse. It prevents the embryo from successfully implanting in the uterine wall.
Another effective means of birth control is the intrauterine device (IUD), plastic and metal (often copper) devise that is inserted into the uterus. While earlier versions were linked to side effects including pelvic inflammatory disease, the currently available forms have few serious side effects and have the advantage of being easily removed when a restoration of fertility is desired. It remains unclear how exactly the IUD exerts its contraceptive effects, but it is thought that it alters the uterine environment to prevent sperm passage or to prevent implantation of the fertilized egg.
The final category of birth control is abortion, which involves the cessation of a pregnancy. It is not a contraceptive technique, given that it does not prevent conception from occurring, but rather, one that terminates an existing pregnancy. This could be performed surgically by removing the fetus from the womb. More recently, drugs that induce a medical abortion such as Ru486 have become available in certain countries, including the United States. This drug, taken during the first trimester of pregnancy, inhibits the effects of progesterone, a hormone that is essential to the continuation of the pregnancy. Thus the fetus is ultimately expelled from the uterus.
While a wide variety of alternatives exist for or birth control, the selection of an appropriate method depends on a wide array of individual circumstances and should be made in conjunction with a knowledgeable health care provider.
Margaret Somosi Saha
Bullough, Vern, and Bonnie Bullough. Contraception: A Guide to Birth Control Methods. Amherst, NY: Prometheus Books, 1997.
Knowles, Jon, and Marcia Ringel. All About Birth Control: A Personal Guide. New York: Crown Publishers, 1998.
Peacock, Judith. Birth Control and Protection: Choices for Teens (Perspectives on Healthy Sexuality). Mankato, MN: Capstone, 2000.