Introduction
Contraception (preventing pregnancy) has been attempted for thousands of years. Over the centuries, contraceptive methods have varied greatly from ways we would consider bizarre to methods quite similar to what we use today. For example, in ancient Egypt, crocodile dung and honey were put in the vagina to prevent conception. In some African countries, women used okra pods as vaginal pouches similar to the female condoms now in use. From dung to seedpods, the effectiveness of traditional contraceptive methods is quite questionable. Although today's methods of birth control can be more complicated to use, they are undeniably more reliable and certainly more appealing.
Over the next 25 years, the world's population is estimated to exceed 8 billion individuals. At more than 40%, this increase represents the largest population growth ever seen over such a short time period. Governments as well as individuals are taking action to keep a huge growth in population from overwhelming resources. Without using some form of family planning, however, approximately 80% of women age 35 to 39 and 91% of women age 20 to 24 would become pregnant at least once during a 5-year period. Even more significant to overall population growth, one out of ten women age 15 to 19 will become pregnant each year, despite a consistent decline in the teen birth rate. Far more likely to live in poverty, babies born to teen-aged mothers are often low in birth weight, which contributes not only to higher infant death rates, but also to greater risk of lifelong health problems. Although estimates vary over a large range, as many as 60% of all pregnancies are believed to be unplanned. Worldwide, unplanned children are more likely to die before the age of one year.
Efforts to control population growth take many forms from governmental limits on the number of children per family to individual decisions about contraceptive methods. Hormonal contraception is just one method of birth control now used to help keep population growth in check and minimize the number of unwanted pregnancies. By far, the most popular method of limiting family size in the United States is oral hormonal contraception taken by the female partner. Since the U.S. Food and Drug Administration (FDA) approved the first modern contraceptive, Enovid 10, in 1960, major advances have been made in hormonal contraception. Available in several different dosage forms, today's hormonal contraceptives are formulated to reduce side effects and increase convenience while maintaining effectiveness.
Important Note: Hormonal contraceptives, in any form, do not provide protection against the spread of sexually transmitted infections (STIs), such as AIDS, gonorrhea, or syphilis (just to name a few).
What is it?
Hormonal contraception is one approach to birth control. It may be accomplished through various methods, which all involve interference with normal sex hormone function in the body. Hormonal contraception for men is under study, but existing hormonal contraception is used almost exclusively by women. Currently-available hormonal contraceptives disrupt the normal menstrual cycle by altering the levels of the female hormones, mainly estrogen and/or progesterone. By changing the amounts of estrogen, progesterone, or both; hormonal contraceptives interfere with the release, fertilization, and/or implantation of human eggs.
Combination contraceptives contain both a synthetic estrogen (usually one known as ethinyl estradiol) and any one of several progestins (synthetic progesterones). Typically, they are taken or used for 3 weeks per month usually being discontinued during the week of the menstrual period. Among the general types of hormonal contraceptives that contain both an estrogen and a progestin are:
Combined oral contraceptive pills (COCs - also known as birth-control pills, OCs, or the "pill") Usually packaged in a compact-like case that holds a one-month supply (either 21 pills that contain active hormones or 21 active pills and 7 inactive placebo "sugar pills"), COCs may be:
- monophasic (all the pills contain the same amounts of both estrogen and progestin)
- biphasic (two different dose levels of the hormones are taken during separate parts of the menstrual cycle)
- triphasic (three different amounts of hormones are used in an effort to better match the normal menstrual cycle and minimize side effects)
Contraceptive patches - adhesive bandage-like squares that stick to the skin and release hormones for one week
Injectable estrogen and progestin combinations (no longer available in the US) - continuous hormone release from once-monthly injections
Vaginal rings - soft circles of vinyl that are saturated with estrogen and a progestin. Inserted once a month into the vagina, they release hormones for 3 weeks before being removed.
Progestin-only contraceptives work mainly by keeping sperm from reaching an egg. They include the following kinds of products:
What causes it?Injectable progestins - usually oil-based products that release a progestin gradually over one to 3 months after a single injection
Intrauterine devices (IUDs) - certain brands contain reserves of a progestin that releases slowly as long as the IUD is in place
Progestin-only pills (also called POPs or "minipills") - tablets taken orally every day
Progestin implants (not currently available in the United States) -progestin-filled rubber or plastic tubes that release a progestin slowly for much longer times (up to 5 years) after being inserted under the skin
Although preventing pregnancy is usually not considered to be a health condition, hormonal contraceptives do represent one of the few drug classes that are widely used by healthy individuals.
How Does Hormonal Contraception Work?
Hormonal contraception upsets normal female hormonal cycles in the human body. Generally, additional amounts of one or two female hormones are used to disrupt the balance of hormones that is needed for pregnancy to occur.
Estrogens:
- prevent ovulation (the release of eggs from the ovaries)
- affect the time needed for an egg to travel through the fallopian tubes, thus interfering with precise timing needed for fertilization
- interfere with the implantation of a fertilized egg on the wall of the uterus
Progestins:
- prevent ovulation (the release of eggs from the ovaries)
- affect the time needed for an egg to travel through the fallopian tubes, thus interfering with precise timing needed for fertilization
- increase the amount and thickness of mucus at the cervix (the opening of the uterus), thereby decreasing sperm entry to and passage through the vagina
- decrease the ability of sperm to fertilize an egg
- interfere with the implantation of a fertilized egg on the wall of the uterus
Currently, all forms of hormonal contraceptives are for use only by women, although several non-hormonal contraceptives (such as condoms) exist for use by men and women.
What are the risk factors?
Certain conditions require careful attention by a healthcare provider when hormonal contraceptives are used. Click on the links below to read about contraindications (reasons not to use certain kinds of hormonal contraceptives) and precautions (reasons to be careful when using certain kinds of hormonal contraceptives) associated with each hormonal contraceptive. Women who have any of the following conditions should discuss the use of hormonal contraception with a doctor before beginning to use it.
- Injectable Estrogen and Progestin Combination (No longer available in the US)
- Contraceptive Patch
- Injectable Progestin
- Progestin-only Pill
- Combination Oral Contraceptive (COC)
- Vagina Ring
- Progestin Implant (not currently available in the US)
- Intrauterine Device (IUD)
What are the symptoms?
Since hormonal contraception is not a health condition, it has no symptoms. It is not absolutely foolproof, however. Pregnancy may occur even when hormonal contraceptives are used correctly and consistently. Women who are using a contraceptive, but who think they may be pregnant, should contact a doctor right away. Hormonal contraceptives should NOT be used during pregnancy. Common signs and symptoms of pregnancy may include:
- Amenorrhea (absence of menstruation)
- Breast tenderness and enlargement
- Darkened nipples
- Frequent urination
- Increased appetite
- Morning sickness (nausea and vomiting, typically early in the day)
- Weight gain
Many types of hormonal and non-hormonal contraceptives are available.
What are the advantages and disadvantages of non-hormonal contraceptive methods?
Non-hormonal Contraceptive Methods Comparison
| Method | Advantages | Disadvantages | |
| Abstinence |
|
| |
| Cervical Cap |
|
| |
| Condom, Female |
|
| |
| Condom, Male |
|
| |
| Diaphragm with Spermicide |
|
| |
| Natural Methods* |
|
| |
| Spermicides Alone |
|
| |
| Sponge |
|
| |
| Tubal Ligation |
|
| |
| Vasectomy |
|
| |
| Withdrawal |
|
|
*Natural Methods include measuring body temperature, tracking menstrual cycles on the calendar, or determining the thickness of cervical mucus
How do hormonal contraceptives compare in cost?
General Cost of Hormonal Contraceptives
(All costs are based on retail prices that were in effect on July 1, 2007)
TABLE KEY:
$ = $0 to $50
$$ = $51 to $100
$$$ = $101 to $150
$$$$ = $151 to $200
$$$$$ = $201+
| Type of Contraceptive | Average Cost Range per Month | |
| Combined Estrogen and Progestin | COC-monophasic* | $ |
| COC-biphasic* | $ | |
| COC-triphasic* | $ | |
| COC-91-day* | $ to $$$ (3-month supply) | |
| Contraceptive patch | $$ | |
| Injectable estrogen and progestin combination | No longer available in U.S. | |
| Vaginal ring | $ | |
| Progestin Only | Injectable progestin* | $$ (3-month supply) |
| Progestin-containing IUD ** | $$$$$ | |
| Progestin-only Pill* | $ to $$ | |
| Progestin Implant | Not currently available in the U.S. |
* A generic form may be available.
**The IUD must be inserted by a physician and additional fees for this service may apply and will vary according to physician.
What are the types of non-hormonal contraceptives?
Abstinence (not having sexual intercourse)
Cervical Cap (a small, cup-shaped latex device that is fitted into the entrance of the vagina to block the passage of sperm)
Condom, Female (a thin, stretchy pouch that fits inside the vagina and keeps sperm from entering the uterus)
Condom, Male (a thin, but strong covering that fits over the penis to prevent sperm from entering the vagina)
Copper IUD (a small T-shaped device wrapped in a copper wire that is inserted into the uterus and may be effective for up to 10 years depending on the device).
Diaphragm (a flexible, rubber device that is held against the opening of the uterus by a spring to prevent sperm from getting into the uterus)
Natural methods (such as measuring body temperature, tracking menstrual cycles on the calendar, or determining the thickness of cervical mucus)
Spermicide (vaginally-inserted chemicals that inactivate sperm - often used in combination with other forms of contraception such as cervical caps, condoms, diaphragms, sponges, and withdrawal)
Sponge (a thick, soft cushion of polyurethane foam that is inserted into the vagina to block the passage of sperm into the uterus)
Tubal ligation or female sterilization (commonly known as tied tubes - a permanent surgical procedure in which the fallopian tubes are cut or blocked so that eggs cannot enter the fallopian tubes and sperm cannot reach the eggs to fertilize them)
Vasectomy or male sterilization (a surgical procedure in which the vas deferens, which are the tubes through which sperm travel, are cut or blocked, so that sperm cannot leave the male body)
Withdrawal (also called coitus interruptus or pulling out taking the penis out of the vagina before sperm is released)
What is Emergency Contraception?
Whether it is the result of a broken condom or a sexual assault, unprotected (without contraception) sexual intercourse may occur. To avoid a possible unwanted pregnancy, emergency contraception may be utilized. Although emergency contraception is often called the ?morning after? pill, it is not a method to use routinely. It should be restricted to just what the name indicates - emergencies.
Currently several methods are used for emergency contraception. The most common methods work by preventing conception. Another way is to force the elimination of a fertilized egg.
In 1999, the FDA approved for use in the United States a contraceptive that is used only to prevent conception in an emergency situation. Under the brand name Plan B, the product has 2 tablets containing the progestin, levonorgestrel. Depending on the time of the woman?s cycle when it is taken, it prevents conception by interfering with ovulation, fertilization, and/or implantation. To use it, the first dose should be taken as soon as possible. A second dose is then taken 12 hours after the first dose. According to study results, Plan B may be up to 95% effective, if the first dose is taken within the first 24 hours and the second dose is taken on time. If the first dose is delayed until 72 hours, effectiveness decreases to about 89%. After 72 hours, effectiveness decreases significantly. In August 2006, the FDA made Plan B a non-prescription product for women who are 18 years old or older. Because it is still a prescription drug for younger women, Plan B will be kept behind the pharmacy counter.
Taking high doses of certain regular COCs may also prevent conception after unprotected sex. Like Plan B, however, this method also loses effectiveness if it is not started quickly. Each dose consists of 2 to 4 tablets of certain COC brands. A woman who needs to use this method, which may also be called the Yuzpe Method (pronounced Yoo-zep-ee), should check with a physician or pharmacist for recommendations on the brand of COC to use and the number of tablets to take. As with Plan B, the first dose of the COC should be taken as soon as possible within 72 hours. A second dose is then taken 12 hours after the first dose.
Common side effects from either Plan B or high doses of COCs may include breast tenderness, headache, nausea, pain in the abdomen, and tiredness. Because many women using Plan B or high dose COC also experience vomiting, an anti-nausea drug may be recommended before taking the first dose. If vomiting occurs within one hour of taking the COC, the dose should be repeated. Neither Plan B nor high doses of a COC can end a pregnancy if a fertilized egg has already implanted in the uterus.
For emergency use, a copper IUD can also prevent fertilization and/or implantation if it is inserted no later than 5 to 7 days after the incident. It is left in place at least until the start of the next menstrual period, but it may be left in place for 5 years or longer, if it is chosen as continuing contraception. With pregnancy prevention nearing 100%, inserting an IUD is more effective for emergency situations than taking oral forms of emergency contraception. IUDs are much more expensive, though, and they have to be inserted, checked, and removed by a doctor. They are not recommended for women who may have or who may have been exposed to an STI. IUDs may cause abdominal cramping and vaginal bleeding in the first few days or weeks after their insertion.
Another method of emergency contraception ends a pregnancy. Sometimes known as a "medical abortion", this method requires that two different drugs be taken. First, one 600 mg dose of mifepristone (Mifeprex) is taken as soon as possible within 49 days of the missed menstrual period. Two days later, one 400 microgram dose of misoprostol (Cytotec) must be taken. Mifepristone, commonly known as RU-486, blocks the effects of progesterone, which is necessary to maintain a pregnancy. Misoprostol belongs to a group of drugs known as prostaglandins, which cause the uterus to tighten. Usually, uterine contents (such as a fertilized egg) are forced out of the uterus. Women who use this form of emergency contraception must follow-up with a physician 14 days after taking misoprostol to determine whether the treatment was effective. Mifepristone/misoprostol is available only through specific physicians who must be able to perform abortive surgery if the treatment is ineffective.
Women with an IUD in place, those taking medications to prevent blood clotting, and those who have taken certain steroid medications for long periods of time cannot use mifepristone/misoprostol. This method also should not be used for women who have or have ever had:
- Adrenal gland dysfunction
- Allergic reactions to mifepristone or misoprostol
- Bleeding disorders
- Ectopic pregnancy (a fertilized egg that has implanted outside the uterus)
- Tubal pregnancy (a fertilized egg that has implanted inside the fallopian tube)
Between 80% and 90% of women who use mifepristone/misoprostol experience abdominal cramps and/or heavy vaginal bleeding. Other common side effects from mifepristone/misoprostol include diarrhea, dizziness, headaches, nausea, and tiredness.
What are the types of hormonal contraception?
Combination oral contraceptives (COCs) contain both an estrogen (usually one called ethinyl estradiol) and a progestin. Different brands may have varying amounts of estrogen and the progestin may be different. In general, lower doses of estrogen cause fewer side effects, so most currently-available COCs contain smaller amounts of estrogen than earlier versions. In addition, the products may have constant or varying amounts of the progestin component - making the pills either monophasic, biphasic, or triphasic. Monophasic COCs have the same amount of the estrogen and the same amount of the progestin in each pill throughout the cycle. Biphasic pills have the same amount of the estrogen, but have two different doses of the progestin at different parts of the menstrual cycle. Triphasic COCs, which are made to mimic the natural changes in hormone levels, have a constant dose of the estrogen with three different amounts of the progestin. Most COCs are prepackaged in compact-like cases that contain either 21 or 28 pills. Women who use the 21-day packs do not take a pill during their menstrual periods. The 28-day packs contain 21 active pills and seven inactive placebo (sugar) pills that are included as reminders so that the individual taking the pills does not forget to start a new pack on time.
A newly-approved COC (Seasonale) introduces a new dosing schedule that is more convenient for women using it. Intended to be taken daily for 12 weeks, the "extended-cycle" COC is then discontinued for one week. As a result, the user has only four periods a year instead of one a month.
Another newly approved COC (Yaz) is taken for 24 days instead of 21 days. This is done to help shorten menstruation as well as possibly decrease side effects due to decreased hormonal fluctuation.
Estrogen containing drugs may increase your chances of developing heart disease. This is especially true if you are a smoker, have diabetes, high cholesterol, or a history of heart disease in your family. A recent study found that even low dose estrogen containing oral contraceptives can increase a woman's risk for a heart attack or stroke. You should always talk with your physician to see if a particular form of birth control is right for you.
Contraceptive patches release hormones through the skin. One patch is applied by the user each week for 3 weeks every month, skipping the fourth week usually the week that menstruation occurs. They are convenient for women who cannot remember to take pills.
Injectable estrogen and progestin combinations are given into a muscle of the arm, thigh, or buttock by a qualified health care professional. They must be injected once a month between days one and 5 of the menstrual cycle. Injectable combination hormonal contraception offers another effective alternative for women who may have difficulty remembering to take pills. Unfortunately, injectable estrogen and progestin combinations are no longer available in the U.S.
Vaginal rings are inserted by the user. After releasing hormones for 3 weeks, they are removed and discarded. A new vaginal ring is then inserted possibly during the menstrual period. Similar to hormonal injections or patches, vaginal rings provide an alternative for women who have difficulty remembering to take pills.
Injectable progestin has been used for contraception since the 1960's, even though it was not FDA-approved for contraception until 1992. Given by injection into an arm or buttock muscle, it must be administered by a health care professional. It is given once every 3 months between days one and 5 of the menstrual cycle. A very effective long-term contraceptive, progestin injection may be an especially good choice for women who are breast-feeding, who have a history of seizures, who should avoid estrogens, who may forget to take pills, or who do not want to use other methods.
Intrauterine devices (IUDs) are small "T"-shaped devices, which may be filled with a progestin. In addition to releasing a progestin, IUDs are believed to cause minor uterine inflammation, change the chemical environment of the uterus, and ? possibly ? interfere with sperm movement. All these effects may destroy the egg or sperm and they may also prevent implantation. IUDs are inserted through the vagina by a qualified health professional. Good candidates for an IUD are women who have a history of seizures, who should avoid estrogens, who have trouble remembering to take pills, who do not want to use other methods, or who want long-term contraception that is not permanent. However, women who use IUDs may have higher risk for both pelvic inflammatory disease (PID) and ectopic pregnancy (a fertilized egg that has implanted outside the uterus).
Progestin-only pills, also called "POPs" or "minipills" offer an alternative to COCs for women who are breast-feeding, smokers over the age of 35, women who have or who have had breast cancer, and other women who cannot take estrogens. They must be taken every day with no breaks during periods. To be as effective as possible, progestin-only pills need to be taken at the same time each day.
Progestin-only implants are not currently available in the United States, although they are used commonly in other parts of the world. They consist of up to six small tubes that contain a progestin. Inserted under the skin on the inside part of the upper arm, the tubes release a constant amount of medication. Their insertion and removal are minor surgical procedures that must be done by a doctor with special training. Insertion is usually done between days one and 7 of the menstrual cycle or after a negative pregnancy test. Progestin-only implants may be removed at any time over a period of one to 5 years depending on the brand and the number of tubes that are inserted.
How effective are various methods of contraception?
Except for total abstinence (never having sex at all), no form of contraception is 100% effective – even if it is used perfectly. Failure rates (the percentage of pregnancies that occur among women who are using each type of contraception) are typically higher during the first year that an individual uses a particular type of contraceptive. Additionally, effectiveness may be influenced by social or economic factors, such as body weight, ethnicity, income level, location, marital status, and frequency of sexual intercourse. For comparison, about 85% of fertile (able to become pregnant) women who do not use any form of contraception may be expected to become pregnant in any one year.
Contraceptive Effectiveness Comparison
| Method | Failure Rate |
| Hormonal Methods | |
| COC | 0.1% to 3% |
| Contraceptive Patch | 0.3% to 1% |
| Injectable Estrogen and Progestin (no longer available in U.S.) | Less than 1% |
| Vaginal Ring | 0.3% to 1% |
| Injectable Progestin | 0.3% to 3% |
| IUD | 1% to 4% |
| Progestin-only Pill | 0.5% to 5% |
| Progestin Implant (not currently available in the U.S.) | 1.5% to 9.3% |
| Non-hormonal Methods | |
| Abstinence (Continual) | 0 |
| Abstinence (Occasional) | Up to 25% |
| Cervical cap | 8% to18%* |
| Condom, Female | 3% to 12% |
| Condom, Male | 3% to 21% |
| Diaphragm (with spermicide) | 2% to 18% |
| Natural Methods** | 1% to 25% |
| Spermicide Alone | 15% to 29% |
| Sponge | 14% to 28% |
| Tubal Ligation | 0.5% to 0.6% |
| Vasectomy | 0.1% to 0.2% |
| Withdrawal | 4% to 27% |
*Failure rates for the cervical cap may reach 30% for women who have had children
**Natural Methods include measuring body temperature, tracking menstrual cycles on the calendar, or determining the thickness of cervical mucus
What is on the horizon?
Currently, several pharmaceutical companies are developing other new combinations, dosing schedules, and formulations of estrogen and/or progestin pills. Generally, the proposed new products are intended to lower the chance of side effects. New progestins that may provide both contraception and additional benefits, such as helping to lower high cholesterol levels, are also being investigated. Potentially, some of these newer contraceptives may be appropriate for women with irregular periods and other women who cannot use COCs that are currently on the market. Other research focuses on completely new delivery methods, such as an estrogen/progestin nasal spray, that would give women more options for combination hormonal contraception.
Other investigation centers on hormonal contraceptives for men. In much the same way that hormonal contraception works for women, changing normal amounts of androgens (male hormones) disrupts a man's fertility. For example, increasing amounts of the male hormone, testosterone; introducing a progestin (a female hormone); or both drastically decreases the production of sperm and/or causes the sperm that are produced to be unable to fertilize an egg. Injections, implants, or pills are the dosage forms most studied for male contraception.
Non-hormonal contraceptives in development include:
Immunocontraception (contraceptive vaccines) By stimulating the body's immune system to produce antibodies against cells or chemicals that are essential to fertilization, various stages of conception may be prevented. Antibodies are natural proteins that are produced by the immune system to attack specific foreign substances in the body. Among the potential antibody targets that have been studied as immunocontraception are sperm, female and male hormones, and the zona pellucida (a membrane that surrounds human eggs). In studies of humans, antibody response has not been consistent, however, and producing enough antibodies to be effective may take a long time. How long the vaccine will remain effective is not clear, and once antibodies are produced, restoring fertility may be difficult or impossible.
N-butyldeoxygalactonojirimycin (NB-DNJ) A drug already being used to treat a genetic disease, NB-DNJ also blocks the production of sperm. In laboratory studies, male mice that were given NB-DNJ stopped producing sperm, eventually becoming sterile after their pre-existing sperm supplies were exhausted. Men taking NB-DNJ also stopped making new sperm. Their inability to fertilize an egg continued for as long as the drug was administered; but gradually returned to normal after the drug was stopped - over about three weeks for mice; about six weeks for humans.
Spermicide/Anti-infectant Combinations Chemicals that kill or disable sperm and also eliminate bacteria, viruses, and other agents that cause sexually-transmitted infections would not only provide contraception, they would also help to control the spread of diseases such as AIDS and other sexually transmitted infections.
Contraceptive Gel In very early stages of testing is a gel that hardens into a permanent, but possibly removable barrier after being inserted into the fallopian tubes. It forms a solid plug that prevents eggs from entering the uterus and sperm from reaching eggs. In animal studies, it has been effective and easy to insert. However, no human studies have been conducted, yet.
