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.
|
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.
|
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.
|
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.
|
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.
|
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.
|
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.
|
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.
|
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.
|
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.
|
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.
|
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).
|
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.
|
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.
|
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.
|
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.
|
Surgical
Sterilization
|
Surgical Sterilization
An extremely safe method of birth control, surgical
sterilization is also a relatively permanent one. In male sterilization, called
a vasectomy, both vas deferens are severed, preventing sperm from reaching the
penis. The concept is the same in female sterilization, in which the fallopian
tubes are cut so that mature eggs cannot come into contact with sperm. Neither
of these procedures affects the patient’s ability to produce sperm or eggs.
Side effects are extremely rare.
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.
|
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.
|
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.
|
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.
|
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.
|
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.
|
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.
|
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.
|
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.
|
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.
