Birth Control.

Birth Control. I INTRODUCTION Birth Control or Contraception, deliberate prevention of pregnancy using any of several methods. Birth control prevents a female sex cell (egg) from being fertilized by a male sex cell (sperm) and implanting in the uterus. In the United States, about 64 percent of women aged 15 to 44 years practice some form of birth control. When no birth control is used, about 85 percent of sexually active couples experience a pregnancy within one year. There are a variety of birth control methods to choose from, although most options are for women. Selecting a method is a personal decision that involves consideration of many factors, including convenience, reliability, side effects, and reversibility (whether the method is temporary or permanent). For instance, some people may prefer a birth control option that provides continuous protection against pregnancy, while others may prefer a method that only prevents pregnancy during a single act of sexual intercourse. Some people might have past illnesses or medical conditions that prevent them from using certain types of birth control methods. Some women may find that certain birth control methods cause uncomfortable side effects, such as irregular menstrual bleeding, weight gain, or mood changes. A person with multiple sexual partners may prefer a birth control method that also offers protection from sexually transmitted infections (STIs). Another important consideration is whether a person ever plans to have children. Most birth control methods are reversible--they do not affect a person's ability to reproduce once the method is halted. But surgical birth control methods cannot, in most cases, be reversed; once a man or woman undergoes the surgery, he or she can no longer reproduce. In addition to choosing the type of method to prevent pregnancy, men and women are faced with a number of other reproductive choices. Experts use the broader term family planning for the process of making decisions about when to have children and how many children to have, as well as strategies for achieving these goals. II EFFECTIVENESS No birth control method, other than abstinence from sex, is 100 percent effective in preventing pregnancy. Some methods are more effective than others, and scientists use two types of pregnancy rates when describing effectiveness. Method effectiveness, or perfect use, is the percentage of pregnancies that occur when a particular method is used correctly and consistently with each act of sexual intercourse. User effectiveness, or typical use, is the percentage of pregnancies that result from average use of the method, which accounts for improper or inconsistent use. This article provides typical use statistics in its overview of birth control methods. III TYPES OF BIRTH CONTROL Birth control methods work in different ways to prevent pregnancy. Some methods prevent sperm from meeting eggs. Others affect a woman's hormones, altering her reproductive cycle. Other birth control methods involve behaviors that alter sexual activity in ways that lessen the chance for pregnancy. A Barrier Methods Barrier methods physically block sperm from entering the uterus to unite with an egg. Barrier methods must be used with each act of sexual intercourse. While they are easy to use, some people feel barrier methods are inconvenient because they interfere with sexual spontaneity. Barrier methods include male and female condoms, the diaphragm, the cervical cap, and spermicides. A1 Male Condom The male condom is a thin sheath made of latex, polyurethane, or less commonly, animal membrane, that fits over an erect penis. During ejaculation (when semen ejects from the penis), the condom catches and holds sperm before it can travel into a woman's uterus. After each act of sexual intercourse the condom is removed and thrown away. The condom is inexpensive, easy to use, and does not require a prescription. It has no known side effects, although those people who are sensitive or allergic to latex should use polyurethane condoms. Male condoms made of latex or polyurethane also protect users against many STIs, including human immunodeficiency virus (HIV), which causes acquired immunodeficiency syndrome (AIDS). With typical use, male condoms are 86 percent effective in preventing pregnancy. Using a condom with other types of birth control, such as a spermicide (chemical that kills sperm) or withdrawal (removing the penis from the vagina just before ejaculation) greatly improves condom effectiveness. A2 Female Condom The female condom, available without a prescription, is an elongated polyurethane sac. A woman inserts the closed end of the sac into the vagina to cover the cervix (the opening of the uterus) and prevent sperm from entering the uterus. The open end of the sac remains outside the vagina for the penis to enter. Like the male condom, the female condom must be thrown away after use and a new one used for each act of intercourse. With typical use, the female condom is 79 percent effective in preventing pregnancy. It also reduces the risk of many STIs. Some people experience genital irritation from the female condom. A3 Diaphragm The diaphragm is a shallow, molded cup of thin rubber with a flexible rim. Before intercourse, spermicide must be placed inside the cup and around the inside of the rim of the diaphragm. The woman then inserts the diaphragm into her vagina so that it covers the cervix, preventing the passage of sperm from the vagina to the uterus. The spermicide kills any sperm that are able to pass by the diaphragm. Diaphragms come in various sizes to fit the cervix. They are available only from health-care professionals who ensure that the device fits properly. With typical use, the diaphragm is about 80 percent effective in preventing pregnancy. A4 Cervical Cap The cervical cap is made of flexible latex rubber and shaped like a thimble. It is smaller than a diaphragm and fits more tightly onto the cervix, where it is held in place by suction. Like the diaphragm, the cervical cap must be fitted by a health-care professional and it should also be used with a spermicide. With typical use, the cervical cap is about 80 percent effective in preventing pregnancy in women who have not given birth, and about 60 percent effective in those who have given birth. A5 Spermicides Spermicides are jellies, creams, foams, suppositories, tablets, or films that block the entrance to the cervix and contain a sperm-killing chemical. They can be purchased without a prescription and used alone or with a condom, diaphragm, or cervical cap. Spermicides used alone must be inserted deep into the vagina before each act of intercourse and a woman should not douche for six to eight hours after intercourse. With typical use, spermicides used alone are effective in preventing pregnancy about 74 percent of the time. They may cause an allergic reaction such as irritation of the vagina or penis. B Intrauterine Device The intrauterine device (IUD) is a small plastic device inserted into a woman's uterus to prevent pregnancy. IUDs prevent pregnancies through a number of mechanisms: they interfere with the movement of sperm and egg, they decrease the ability of sperm to fertilize an egg, or, rarely, they prevent a fertilized egg from implanting in the lining of the uterus. An IUD must be inserted and removed by a health-care professional. Depending on the device, it must be replaced every one to ten years. A plastic string attached to the IUD hangs down through the cervix, enabling a woman to check regularly that the IUD is properly positioned. With typical use, the IUD is about 96 percent effective in preventing pregnancy. The device may increase menstrual bleeding or cause irregular bleeding or cramping. The IUD has also been associated with an increased risk for pelvic inflammatory disease (PID), an infection of the reproductive tract. However, most cases of PID that occur in women with IUDs are attributable to an STI. Other possible problems associated with IUD use include perforation of the uterus and embedding of the IUD in the uterus. In rare cases an ectopic pregnancy occurs, a serious medical complication in which a fertilized egg implants outside of the uterus. C Hormonal Contraceptives Hormonal contraceptives deliver doses of female sex hormones that alter a woman's reproductive cycle in one or more ways. When absorbed by the body, these hormones may interfere with ovulation to prevent the maturation and release of an egg from the ovaries; thicken the cervical mucus, which interferes with sperm movement; alter the rate at which the egg moves through the fallopian tubes to prevent sperm from meeting the egg; or change the condition of the uterine lining to prevent fertilized eggs from implanting in it. Available only by prescription, hormonal contraceptives are extremely effective in preventing pregnancy when used properly. Many people prefer them because their use does not interfere with sexual spontaneity. Among the drawbacks are reduced effectiveness when used in conjunction with some medications and lack of protection against STIs. Hormonal contraceptives may be administered by pill form, implant, injection, or through vaginal rings or skin patches. C1 Birth Control Pill The birth control pill, or oral contraceptive, was first approved for use in the United States in 1960. These early pills contained high doses of female sex hormones that have since been found to cause long-term health problems, such as blood clotting. The birth control pills available today have much lower doses of hormones. The most common type of birth control pill is the combination pill, which contains low doses of both estrogen and progestin (a synthetic form of progesterone). Another type of birth control pill contains only progestin. To prevent pregnancy a woman takes one birth control pill each day for 21 days, after which she takes no pill or a placebo (a pill containing no active ingredients) for 7 days. With typical use, the pill is 95 percent effective in preventing pregnancy. In addition to its effectiveness as a birth control method, the pill can relieve menstrual pain and reduce menstrual bleeding. It may also offer some protection against PID, endometrial and ovarian cancer, endometriosis (growth of uterine tissue outside the uterus), and uterine fibroid tumors (benign growths). Adverse side effects can include breakthrough bleeding (bleeding between periods), headache, hypertension, weight gain, mood change, decreased sexual desire, blood clotting disorders, cardiac complications, breast tenderness, and galactorrhea (discharge of milk from the breast). C2 Hormonal Implant With typical use, hormonal implants are the most highly effective form of birth control except for continuous abstinence and surgical sterilization. A health-care professional implants a matchstick-sized tube filled with a synthetic progesterone-like hormone called etonogestrel (progestin) just under the skin of a woman's upper arm. The implants can remain in place up to three years. Adverse side effects include irregular intervals between menstrual periods, breakthrough bleeding, headache, acne, weight gain or loss, depression, breast tenderness, and infection or skin discoloration at the implant insertion point. The only long-term hormonal implant approved for use in the United States is sold under the brand name Implanon. C3 Contraceptive Injection Contraceptive injections contain synthetic hormones that a health-care professional injects into the muscles of a woman's buttocks or arm. This form of birth control requires regular visits to a clinic so that a health-care professional can administer the injection. With typical use, contraceptive injections are about 99 percent effective in preventing pregnancy. There are two types of contraceptive injections: Depo-Provera and Lunelle. Depo-Provera contains the synthetic hormone progestin and protects against pregnancy for 12 weeks. Lunelle contains a combination of estrogen and progestin and must be injected once a month. The most common side effect of contraceptive injections is irregular bleeding. For most women periods become lighter and less frequent, and they may stop altogether. Some women may develop heavier and longer periods. Other adverse side effects include breakthrough bleeding, weight gain, headache, sore breasts, depression, nausea, vaginal dryness, and acne. C4 Contraceptive Ring The contraceptive ring, sold under the brand name Nuvaring, is a small flexible ring containing a combination of estrogen and progestin. Each month a woman inserts a new ring deep into the vagina, leaving it in place for three out of four weeks. Unlike a diaphragm or cervical cap, the contraceptive ring does not require fitting by a health-care professional or the addition of spermicide. With typical use, the contraceptive ring is 95 to 99 percent effective in preventing pregnancy. Adverse effects include increased vaginal discharge and vaginal irritation or infection. C5 Contraceptive Patch The contraceptive patch, sold under the brand name Ortho Evra, is a thin, plastic patch containing a combination of estrogen and progestin. A woman applies the patch to the skin of the buttocks, stomach, upper arm, or upper torso once a week for three out of four weeks. The skin absorbs the hormones, which alter the woman's reproductive cycle to prevent pregnancy. Some adverse reactions from the patch include a skin reaction at the application site. Like the contraceptive ring, the patch is effective in preventing pregnancy 95 to 99 percent of the time with typical use. In February 2006 the United States Food and Drug Administration (FDA) advised women using the patch to consult with their physicians after preliminary results from a study found that women using the patch had a higher risk for blood clots than women taking the pill. Current warning labels on the Ortho Evra patch note that women using the patch receive 60 percent more estrogen than those who use birth control pills. Women who smoke should not use the patch because of increased risk of stroke and heart attack, according to health officials. D Surgical Sterilization Methods of surgical sterilization--vasectomy for men and tubal sterilization for women--are almost 100 percent effective in preventing pregnancy. These procedures are permanent forms of birth control. Although surgical techniques may be used to reverse vasectomy or tubal sterilization in some cases, no one should undergo sterilization with the expectation that it can later be reversed. A vasectomy or a tubal sterilization does not protect against STIs. A vasectomy is performed in a doctor's office or clinic using local anesthesia. In this minor surgical procedure, each of the two vas deferens (ducts that carry sperm from the testes to the penis) is cut and the ends are tied off to prevent sperm from reaching the penis. Tubal sterilization is a more complicated surgical procedure performed under general or spinal anesthesia or local anesthesia with a sedative. In this procedure the fallopian tubes are cut and tied, blocked, or sealed to prevent eggs from descending from the ovaries to encounter sperm. E Emergency Contraception Emergency contraception refers to methods that a woman can use after unprotected intercourse to prevent fertilization of the egg or implantation of the fertilized egg in the uterus. Two methods are available: emergency contraceptive pills or emergency insertion of an IUD. Emergency contraceptive pills, commonly called morning-after pills, are similar to birth control pills but they contain a higher dose of hormones. Following a Food and Drug Administration ruling in 2006, women 18 and older can obtain the pills at a pharmacy without a prescription. Teenage girls 17 and younger need a prescription for the pills from a health-care professional. The pills are usually taken in two doses, 12 hours apart. With typical use, emergency contraceptive pills are 79 to 85 percent effective when a woman takes the pills within 72 hours of unprotected intercourse. Depending on where a woman is in her menstrual cycle at the time she takes these contraceptives, the pills will either inhibit or delay ovulation, or they may alter the uterine lining, preventing implantation of a fertilized egg. The insertion of an IUD within seven days of unprotected intercourse is 99 percent effective in preventing pregnancy with typical use. A trained health-care professional must insert the device, which is guided into the vagina and then through the cervix into the uterus. The IUD interferes with sperm movement and the ability of a fertilized egg to implant in the uterine lining. F Fertility Awareness Methods Fertility awareness methods are a collection of practices that help a woman know which days of the month she is most likely to get pregnant. A woman is most fertile during a period that ranges from five days before ovulation to two days after ovulation. A woman can learn when she is ovulating by observing her body and charting physical changes. During the days surrounding ovulation, she can then abstain from sexual intercourse (known as periodic abstinence or natural family planning) or use a barrier method of contraception during intercourse. With typical use, fertility awareness methods are generally about 80 percent effective in preventing pregnancy. Fertility awareness methods are most reliable for women with regular menstrual cycles. As a woman becomes more familiar with the signs of ovulation and the pattern of her menstrual cycle, fertility awareness methods become more effective. Fertility awareness methods require a high level of commitment to consistently and accurately monitor ovulation. Most experts recommend using more than one method to more accurately determine a woman's fertile period. Some couples find abstinence from sexual intercourse during the fertile period inconvenient. In addition, fertility awareness methods do not provide protection against STIs. Methods that can help predict ovulation include monitoring the lengths of menstrual cycles, measuring basal body temperature, and observing changes in cervical mucus. F1 Calendar Charting In calendar charting a woman uses past menstrual cycles as a guide to predict ovulation dates. Over a period of 8 to 12 months she keeps a record of the dates of her first day of menstruation. From this record she can calculate the average number of days in her menstrual cycle, and estimate the day in her cycle when she is most likely ovulating. F2 Basal Body Temperature Measurement In the basal body temperature method a woman takes her temperature at the same time each morning before getting out of bed. In most women, body temperature rises about one degree on the day of ovulation and stays raised for several days. A woman can keep a record of her basal body temperature over a period of 8 to 12 consecutive months to determine the time in her cycle when she ovulates. The primary drawback of using this method by itself is that many factors can raise body temperature, including illness, lack of sleep, and alcohol or drug use. F3 Cervical Mucus Monitoring The cervical mucus method of determining fertility requires a woman to monitor the consistency of her cervical mucus. Cervical mucus changes consistency during the menstrual cycle and plays a vital role in fertilization of the egg. Mucus that is clear, wet, and sticky or elastic appears in the days preceding ovulation and aids in drawing sperm into the fallopian tubes where fertilization usually takes place. It also helps maintain the survival of sperm inside the woman's body. Cervical mucus that is dry, cloudy, or yellowish indicates that ovulation is not occurring. One drawback of this method is that the consistency of cervical mucus can be altered by the use of douches or spermicides, making it difficult for a woman to identify changes. G Withdrawal Withdrawal is the deliberate removal of the penis from the vagina before ejaculation so that sperm is not deposited in or near the vagina. This method of contraception is not recommended, because drops of fluid secreted by the penis when it first becomes erect can contain enough sperm to cause pregnancy. In addition, a man may not withdraw in time. With typical use, withdrawal is effective in preventing pregnancy 81 percent of the time. Withdrawal does not protect against STIs. H Continuous Abstinence Abstinence is the avoidance of any sexual activity that could cause pregnancy. This includes intercourse and other sexual activities in which semen may come in contact with the vulva (external female genitals) or vagina. Abstinence is completely effective in preventing pregnancy as well as STIs, and it poses no health risks. IV CURRENT RESEARCH IN BIRTH CONTROL Researchers are currently developing a number of birth control options for men, including hormonal contraceptive pills and implants. An injection for men under investigation contains a hormone that appears to interfere with the production of sperm. Reversible methods of vasectomy are also being explored. Drugs known as gonadotropin-releasing hormone (GnRH) agonists are being investigated as birth control options for men and women. These drugs prevent the release of follicle-stimulating hormone (FSH) and luteinizing hormone (LH) from the pituitary gland, which, in turn, blocks ovulation in women and spermatogenesis (the development of sperm) in men. Researchers are also developing improved versions of existing birth control options. New types of diaphragms may one day include a one-size-fits-all device and a disposable, spermicide-releasing diaphragm. Other research focuses on biodegradable hormonal implants designed to dissolve in the body and new spermicidal preparations that would better protect against STIs. A History and Social Issues of Birth Control A variety of birth control methods have been used throughout history and across cultures. In ancient Egypt women used dried crocodile dung and honey as vaginal suppositories to prevent pregnancy. One of the earliest mentions of contraceptive vaginal suppositories appears in the Ebers Medical Papyrus, a medical guide written between 1550 and 1500 BC. The guide suggests that a fiber tampon moistened with an herbal mixture of acacia, dates, colocynth, and honey would prevent pregnancy. The fermentation of this mixture can result in the production of lactic acid, which today is recognized as a spermicide. Before the introduction of the modern birth control pill, women ate or drank various substances to prevent pregnancy or induce miscarriage. The seeds of Queen Anne's lace, pennyroyal, giant fennel, and many other concoctions of plants and herbs were used as oral contraceptives. However, such folk remedies can be dangerous or even fatal. The concept of the IUD was developed by ancient Turks and Arabs who inserted smooth pebbles into the uterus of a camel to prevent it from getting pregnant during treks across the desert. The use of colorful penis coverings can be traced back to ancient Egypt, but it is likely that their function was more decorative than contraceptive. In the 16th century the Italian anatomist Gabriello Fallopio (for whom the fallopian tubes that carry the eggs from the ovary to the uterus were named) described linen sheaths to be used to protect against syphilis. In the 17th century a physician in the court of King Charles II of England created a condom made of sheep intestines. Italian adventurer Giacomo Casanova is said to have referred to the device as an "English riding coat." It was not until after the vulcanization of rubber in 1839 that the condom was widely used as a birth control device. German physician Wilhelm Mensinga invented the modern diaphragm in 1880. The cervical cap was invented in 1860, but it did not receive the approval of the Food and Drug Administration for use in the United States until the late 1980s, despite its widespread use in Europe. Concerns about overpopulation have also existed since ancient times. The Greek philosophers Plato and Aristotle warned of its dangers. In his essay De Anima, Roman philosopher Tertullian commented on the blessing of catastrophes that help curb overpopulation. In the 18th century British economist Thomas Malthus made overpopulation a topic of scholarly discussion. He was one of the first to apply statistics to the analysis of population growth. This approach became the science of demography. Malthus was concerned about the human potential to produce offspring in far greater numbers than the Earth's ability to provide subsistence. In his "Essay on the Principle of Population," published in 1798, Malthus advocated what he termed "moral restraint" in the form of strict premarital chastity and delayed marriage to curb population growth. Malthus's views were attacked by many as pessimistic, unsympathetic to the poor, and unrealistic in terms of his proposed solution. The birth control movement grew out of Malthus's concerns, and his successors advocated more practical methods of contraception. Margaret Sanger, an American nurse, pioneered the modern birth control movement in the United States. In 1912 she began publishing information about women's reproductive concerns through magazine articles, pamphlets, and several books. In 1914 Sanger was charged with violation of the Comstock Law, federal legislation passed in 1873 prohibiting the mailing of obscene material, including information about birth control and contraceptive devices. In defiance of the Comstock Law and despite being jailed for these activities, Sanger continued to publish and disseminate information about birth control. In 1916 Sanger and her sister Ethel Byrne opened the first of several birth control clinics in Brooklyn, New York. Congress revised the Comstock Law in 1936 to exclude birth control information and devices. Many states had laws prohibiting distribution or use of birth control devices but the constitutionality of these laws was increasingly questioned. In 1965, in Griswold v. Connecticut, the Supreme Court of the United States ruled that married people have the right to practice birth control without government intervention. In 1972, in Eisenstadt v. Baird, the Court held that unmarried people have the same right. Today there are more birth control options than ever before, but overpopulation and unwanted pregnancies remain worldwide problems. Having more children than one can support may lead to poverty, malnutrition, illness, and high mortality rates for infants, children, and women. The problem of teenage pregnancy is considerably worse in the United States than in almost any other developed country. Among developed countries, the United States has one of the highest birth rates for women under 20. A detailed study comparing Canada, England and Wales, France, The Netherlands, Sweden, and the United States suggested that the problem of teen pregnancy in the United States may be related to less sex education in schools and lower availability of birth control services and supplies to adolescents. This study counters the view of some people in the United States who argue that sex education or making birth control devices such as condoms available to school-age children promotes sexual activity. Microsoft ® Encarta ® 2009. © 1993-2008 Microsoft Corporation. All rights reserved.