Contraception (birth control) prevents pregnancy by interfering with the normal process of ovulation, fertilization, or implantation. There are differentkinds of birth control that act at different points in the process.

Every month, a woman's body begins the cycle that can potentially lead to pregnancy. An egg 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 thickens in preparation for receiving afertilized egg.

Birth control is designed to interfere with the normal process and prevent pregnancy. Each method has its own side effects and risks, but some are more reliable than others. Although there are many different types of birth control,they can be divided into several groups based on how they work. Birth control choices include natural contraception, in which a couple has sex during certain periods of a woman's menstrual cycle when she's least likely to get pregnant; hormonal methods using hormone implants and injections that interfere with ovulation, conception or implantation; barrier methods including condoms,diaphragms, cervical caps and sponges that physically prevent sperm from getting into the reproductive system and fertilizing an egg; intrauterine devices that are inserted into the uterus to prevent pregnancy.

There are also a number of methods that are not effective as a means of birthcontrol:

  • sex during a period: There's still a slim chance a woman canget pregnant
  • douching after sex: it's not possible to destroy all the sperm by douching; they may be forced higher into the uterus
  • urinating after sex: urine and sperm travel in two separate parts of the body, so urinating won't have any affect on sperm travelling up the vagina
  • washing after sex: no matter how fast you think you can wash, sperm are already swimming madly through the cervix, where they won't be destroyed by washing
  • early withdrawal: even if the penis is removed before ejaculation, there is usually some sperm in the pre-ejaculatory liquid (the penis doesn't needto be inside the vagina for some sperm to make it through the cervix and fertilize an egg)

Only abstinence (not having sexual intercourse) can protect against unwantedpregnancy with 100% reliability. The failure rates for most forms of birth control are quite low. However, some forms of birth control are more difficultor inconvenient to use than others. In practice, the birth control methods that are more difficult or inconvenient have much higher failure rates becausethey are not used consistently.

Natural Methods

For many reasons (mostly religious or health), some couples rely on natural family planning as their main method of contraception: not having sex on the days of a menstrual cycle when the woman could get pregnant. Because sperm maylive in the reproductive tract for up to seven days (and an egg remains fertile for about 24 hours) a woman can still get pregnant from seven days beforeovulation to three days after. It's possible to figure out fertility times by using methods based on the menstrual cycle, changes in cervical mucus, or changes in body temperature.

Hormonal methods

Given in the form of injections, pills or implants, hormones can interfere with normal ovulation, conception and implantation very effectively. Unfortunately, they also can cause a range of side effects, including headaches, acne,weight changes, excess hair or hair loss, nausea, vomiting, depression, and menstrual irregularities. Despite these problems, they're a popular choice formany women because they are easy to use and highly effective. Implants and injections in particular can be a good choice since they are estrogen-free andthey are easy to use.

Oral contraceptives have been on the market for more than 35 years and are the most popular form of reversible birth control in the United States. "The Pill" works by suppressing ovulation (the monthly release of an egg from the ovaries) by the combined actions of the hormones estrogen and progestin. Womenwho take the pill every day as directed have an extremely low chance of becoming pregnant. However, the pill's effectiveness may be reduced if a woman takes certain medications (such as antibiotics).

In the past, strong versions of the pill with high doses of estrogen made this type of contraception dangerous for women over age 35; newer, safer forms are now highly effective and reasonably safe for most nonsmoking women up to age 45. Still, the long-term effect of taking these pills is not clear. Whilebirth control pills are safe for most women, they do carry some risks; low-dose pills have fewer risks associated with them than earlier versions. Possible side effects include nausea, headache, breast tenderness, weight gain, irregular bleeding, and depression. In addition, the pill may contribute to highblood pressure, blood clots, and blocked arteries.

In the past, critics have been concerned about a possible link between the pill and breast cancer, but recent research suggests that a woman's risk of breast cancer 10 years after going off birth control pills was no higher than that of women who had never used the pill. During pill use and for the first 10years after stopping the pill, a woman's risk of breast cancer was only slightly higher in pill users than non-pill users. Most health experts advise thefollowing women not to take the pill:

  • women who smoke--especially those over 35
  • women with a history of blood clots
  • women with a history of breast or endometrial cancer
  • women with heart disease

Another type of oral contraceptive called the "minipill" is taken daily, butcontains only the hormone progestin--with no estrogen. This works by reducingand thickening cervical mucus to prevent sperm from reaching the egg. Thesepills also keep the uterine lining from thickening, which prevents a fertilized egg from implanting in the uterus. Because they lack estrogen, these pillsare slightly less effective than combined oral contraceptives. Minipills candecrease menstrual bleeding and cramps, as well as the risk of endometrial and ovarian cancer and pelvic inflammatory disease. Because they contain no estrogen, minipills don't present the risk of blood clots associated with estrogen in combined pills. They are a good option for women who can't take estrogen because they are breast-feeding or because estrogen-containing products cause them to have severe headaches or high blood pressure. Side effects of minipills include menstrual cycle changes, weight gain, and breast tenderness.

Birth control methods that include hormones (birth control pills, hormone injections or hormone implants) can affect other medications or lab test results. Women using one of these methods should be sure to tell any doctor who is going to prescribe medicine.

One of the newer types of birth control options are contraceptive implants--small, matchstick-sized tubes containing a progestin or levonorgestrel--inserted just under the skin of the arm. Once in place, the implants release a small amount of hormone each day for five years, blocking ovulation and thickening cervical mucus. The implants are probably the most effective method of contraception available. Once the implants are removed, a woman can get pregnantagain. The six-rod Norplant implant provides protection for up to five years(or until it is removed), while the two-rod Norplant 2 protects for up to three years. Norplant failures are rare, but are higher with increased body weight.

The implants can be inserted during an office visit, imbedded under the skinin the upper arm. They must be surgically removed, which may be difficult. Some women may experience inflammation or infection at the site of the implant.Other side effects include menstrual cycle changes, weight gain, breast tenderness, and bone mass loss. Women should not use implants if they:

  • are(or might be) pregnant
  • have unexplained unusual vaginal bleeding
  • take antiseizure drugs
  • take the antibiotic rifampin
  • haveblood clots in your veins
  • have had pulmonary embolism (blood clots in your lungs)

Hormone injections, which are considered to be safe and effective as a type of birth control, include a long-acting type of progesterone which is injectedinto a woman's body every three months. The injection prevents ovulation; when taken as scheduled it's more than 99% effective and completely reversibleonce the hormone is eliminated from the body. (A shot should be given withinfive days of the start of the menstrual period to get full protection from pregnancy right from the beginning). A woman should avoid the injections if there is a possibility of pregnancy or there has been any unexplained vaginal bleeding in the previous three months. Once a woman has received the injectionthere is no way to become fertile again until it wears off about three monthslater.

Because the injections aren't metabolized in the liver, it's possible to avoid some of the side effects that come with pills, but there still may be:

  • abdominal discomfort
  • nervousness
  • decreased sex drive
  • depression
  • acne
  • dizziness
  • weight gain
  • menstrual cycle disruption
  • bleeding and spotting

"Morning after" pills are used in emergency contraception after a woman has had unprotected sex (such as after a rape). It cannot be used to terminate analready-established pregnancy. Doctors sometimes prescribe higher doses of combined oral contraceptives for use as "morning after" pills to be taken within 72 hours of unprotected intercourse to prevent the possibly-fertilized eggfrom reaching the uterus. While there's no guarantee, the morning-after pillprobably cuts the chance of getting pregnant by 89% to 95% (effectiveness declines the delay between sex and the morning after pill). The "morning after"pill was officially recognized as safe and effective by the Food and Drug Administration in February 1997.

Scientists aren't sure exactly how it works, but they suspect that the largedoses of hormones prevent the lining of the uterus from getting thick enoughto allow an egg to implant or that they interfere with ovulation in some way,slowing the way the egg travels through the fallopian tube. Unfortunately, the larger dose of hormones may cause side effects similar to (but stronger than) the side effects with a regular dose of birth control pills. The next period may be late because of the pills, but if there is no period within threeweeks of treatment, pregnancy needs to be ruled out.

Barrier methods

Barrier methods of birth control physically stop sperm from getting into theuterus (and the spermicide used with many methods also kill sperm). When usedwith spermicide, barrier methods are among the safest and cheapest ways to prevent pregnancy--and they can also help reduce the risk of being infected with certain sexually transmitted diseases (STDs), pelvic inflammatory disease,and perhaps even cervical cancer. However, if used inconsistently or incorrectly, barrier methods have a relatively high pregnancy rate. Barrier methodsare usually used with some type of spermicide, which kills sperm on contact,and are sold as a foam, cream, jelly, film, suppository, or tablet. Accordingto a 1996 FDA advisory committee panel, some vaginal spermicide containing nonoxynol-9 may reduce the risk of gonorrhea and chlamydia transmission. However, nonoxynol-9 may cause tissue irritation, boosting the risk of some STDs,including HIV.

Male and female condoms are designed as a latex or polyurethane barrier to sperm; the male version fits over the erect penis and the female type is inserted into the vagina, covering the cervix inside and the lips of the vagina outside. Some have spermicide added to kill sperm, although adding spermicide doesn't seem to improve the protective rate any further. In addition to preventing pregnancy, condoms prevent direct contact with semen, infectious genitalsecretions, and genital lesions and discharges.

Most condoms are made from latex rubber (hence their nickname, "rubber"), butpolyurethane condoms are an alternative choice for those who are allergic tolatex. A few types are made from lamb intestines; these don't always preventSTDs because they're porous and may permit passage of viruses like HIV, hepatitis B and herpes.

Some condoms are prelubricated, but these lubricants don't provide more birthcontrol or STD protection. Non-oil-based lubricants (such as water or K-Y jelly), can be used with latex or lambskin condoms, but oil-based lubricants such as petroleum jelly (Vaseline), lotions, or massage or baby oil should notbe used because they can weaken the condom material. Used alone, the male condom has an expected failure rate of 2% and a typical failure rate of 12% (mostly because it can slip or break during withdrawal). Used with spermicide, the failure rate can be reduced almost to zero.

Female condoms, approved by the FDA in 1993, are sold under the brand names Femidom and Reality. Less likely to slip or burst than the male version, the female condom is a lubricated polyurethane sheath with a closed flexible ringat one end and a larger open ring at the other. The closed ring is inserted into the vagina and fitted over the cervix, leaving the open end hanging outside the vagina where it partially covers the labia. It must be carefully removed after sex; another must be inserted each time sex is repeated. Used correctly, the female condom is as effective as the diaphragm or cervical cap. However, the male and female condoms should not be used at the same time becausethey may not both stay in place.

The diaphragm is available by prescription only and fitted by a doctor. Its dome-shaped rubber disk and flexible rim covers the cervix so sperm can't reach the uterus, while the spermicide applied to the diaphragm before insertionkills sperm. It protects for six hours; after that time (or for repeated intercourse within this period), fresh spermicide should be inserted with the diaphragm still in place. It should not be left for longer than 24 hours becauseof the risk of toxic shock syndrome (TSS), a rare but potentially fatal infection. Used consistently and correctly, the diaphragm has a failure rate of about 6% (although the typical failure rate is closer to 18% because people don't always use it consistently).

The cervical cap is basically a smaller type of diaphragm that fits over thecervix and is held in place by suction. The soft rimmed rubber cup is about the size of a thimble and is fitted by a doctor. It's available by prescription only and is used with spermicide (which also may be enough to help preventthe spread of certain STDs). The cap can be worn for 48 hours and for multiple acts of intercourse within this time. Wearing it for more than 48 hours isnot recommended because of the low risk of toxic shock syndrome. If used formore than two days, the cap may cause an unpleasant vaginal odor or dischargein some women. Because it can be difficult to insert and doesn't fit all women, it's a less popular method than the diaphragm. On the other hand,it can be left in place longer than the diaphragm and can be used to collect menstrual blood.

The sponge is a donut-shaped polyurethane device containing the spermicide nonoxynol-9 that is inserted into the vagina to cover the cervix, much like a diaphragm. A woven polyester loop is attached for easy removal. The sponge isa low cost, nonprescription product that protects for multiple acts of sex for 24 hours. It should remain in place for at least six hours after sex for contraceptive protection, but no more than 30 hours after insertion because ofthe slight risk of toxic shock syndrome. The sponge (Today) had been taken off the market in 1995 for financial reasons. The sole manufacturer, WhitehallLaboratories of Madison, N.J., decided it would cost too much to correct manufacturing problems the FDA had discovered. (The FDA stressed that there neverwas any problem with Today's safety, just with the factory.) About 116,000 American women had been using the sponge when its manufacturer stopped production, making it the most popular choice among methods that didn't require a doctor's visit. The only other nonprescription choices were spermicide and maleand female condoms; unlike those options, the sponge could be inserted up to24 hours before sex and didn't require new applications for repeated intercourse.

Although competing sponges were sold in France, Canada and a few other countries, but once Today was off the U.S. market, no contraceptive sponge was soldin this country until 1999, when the sponge was brought back by Allendale Pharmaceuticals of New Jersey. Because the FDA never revoked the Today's approval, getting it back on the market was not difficult.

Intrauterine Device

An IUD is a T-shaped device inserted into the uterus by a doctor. Today thereare only two types of IUDs legally available in the United States: the Paragard Copper T 380A and the Progestasert Progesterone T. The Paragard can remain in place for 10 years, while the Progestasert IUD must be replaced every year.

During the 1970s, the Dalkon Shield IUD was taken off the market because it was associated with a high incidence of pelvic infections and infertility, andsome deaths. Today, serious complications from IUDs are rare, although IUD users may be at increased risk of developing pelvic inflammatory disease. Other side effects can include perforation of the uterus, abnormal bleeding, andcramps. Complications occur most often during and immediately after insertion.

It's not entirely clear how IUDs prevent pregnancy, but they appear to prevent sperm and eggs from meeting by either stopping sperm on the way to the fallopian tubes or changing the uterine lining so the fertilized egg cannot implant in it. IUDs have one of the lowest failure rates of any contraceptive method (a typical failure rate of about 3%), and is a very safe and effective method of contraception. Still, because of menstrual cramps and heavy bleeding,many women have their IUDs removed during their first year. Because women whohaven't yet had children experience a higher risk of developing pelvic inflammatory disease with the IUD, most doctors won't use one with a woman who isstill interested in having children.


Surgical sterilization is a contraceptive option intended for people who don't want children in the future. It's considered permanent because reversal requires major surgery that is often unsuccessful. In general, vasectomy (male sterilization) is less expensive and less risky than female sterilization). Ifone of a couple has been sterilized and now is considering reversal, the other partner should be examined for infertility before the reversal operation is attempted.

A vasectomy is a type of male sterilization in which the doctor seals, ties or cuts the vas deferens (the tube which carries the sperm from the testicle to the penis). Vasectomy is a quick operation (usually under 30 minutes) withonly minor postsurgical complications such as bleeding or infection. A man can have sex a few days after surgery, but there may still be some mature spermin the reproductive tract, so pregnancy could still result. Typically, a manshould ejaculate 15 times after a vasectomy before he's infertile. It's bestto use some sort of backup birth control method until a doctor can verify the sperm count is zero.

To sterilize a woman, a doctor blocks the fallopian tubes with various surgical techniques so the egg can't travel to the uterus. Sterilization is usuallydone under general anesthesia with laparoscopy to cut and tie both fallopiantubes so that the egg released each month by an ovary can't come in contactwith sperm. In this procedure, the doctor will introduce gas into your abdomen to push the intestines away from the uterus and fallopian tubes, and then insert a lighted tube (laparoscope) through the same incision. Next, instruments are introduced through the laparoscope (or a smaller second incision at the public hairline); the doctor then seals the fallopian tubes using one of these methods:

  • tubal ligation: Also known as "tying the tubes," the doctors tie surgical sutures around the fallopian tubes in two places, removing the section between the ties
  • electrocoagulation: the doctor burns thewalls of the fallopian tubes with electrical energy so that the two parts ofthe tubes are blocked
  • mechanical blocks: clips or bands block and crush the fallopian tubes

Complications are rare, but they may include infection or damage to the bowelor blood vessels, or problems related to general anesthesia. Some studies suggest that sterilization may cause changes in a woman's menstrual cycles or lead to abdominal pain later. In addition, some women sterilized when they were younger appear to be more likely to need hysterectomies later on than womenwho were not sterilized.


Very few birth control devices are 100% foolproof; too many times, people don't use the methods correctly or consistently. In the event of an unplanned pregnancy, a couple has the choice of ending the pregnancy or carrying the babyto term. If the pregnancy will be terminated, the woman should seek help from an experienced abortion provider, since the earlier a pregnancy is ended, the less dangerous to the mother. Although abortion is currently legal in theUnited States, some states do have mandatory waiting periods, some require parental involvement for minors, and some require that a doctor present graphicmaterial designed to discourage abortion.

A "medical abortion" is an abortion triggered by the use of drugs. Mifepristone (formerly known as the "French abortion pill" or RU 486) is only availablein limited settings in the United States, although FDA approval is expected.Unlike surgical abortion, which is often not done before the seventh or eighth week of gestation, medical abortion can be used earlier--as soon as pregnancy is determined. The drugs use antiprogestins which block the action of natural progesterone; without progesterone's effects, the uterine lining softensand breaks down, leading to menstruation. This is most effective when used in the first weeks after fertilization and implantation, when progesterone isbeing produced mostly bye the ovaries. As pregnancy proceeds, the placenta takes over progesterone's role, and the antiprogestins are less effective.

A surgical abortion is the only type of FDA-approved abortion currently available in the U.S.; in some states, it's very hard to obtain. Abortion servicesare offered in hospitals and clinics, and usually are done before 12 weeks of gestation. After 11 to 12 weeks, complication rates escalate. The most common technique is to use suction to remove the uterine contents; if the pregnancy is beyond 15 weeks, the process is more complicated because of the size ofthe fetus. After a surgical abortion, women will experience light to mediumbleeding over five to seven days, and cramps. Most doctors recommend not having sex until the cervix has closed (usually when the bleeding stops).

There is no perfect form of birth control. Every method has a small failure rate and side effects. Some methods carry additional risks. However, eery method of birth control has fewer risks than pregnancy.

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