Birth control is a regimen of one or more actions, devices, or medications followed in order to deliberately prevent or reduce the likelihood of a woman becoming pregnant or giving birth. For many people, birth control is an integral component of family planning. Mechanisms which are intended to reduce the likelihood of the fertilisation of an ovum by a spermatozoon may more specifically be referred to as contraception.

Methods

Physical methods
Barrier methods place a physical impediment to the movement of sperm into the female reproductive tract.
The most popular barrier method is the male condom, a latex or polyurethane sheath placed over the penis. The condom is also available in a female version, which is made of polyurethane. The female condom has a flexible ring at each end — one secures behind the pubic bone to hold the condom in place, while the other ring stays outside the vagina.
Cervical barriers are devices that are contained completely within the vagina. The contraceptive sponge has a depression to hold it in place over the cervix. The cervical cap is the smallest cervical barrier. It stays in place by suction to the cervix or to the vaginal walls. The Lea's shield is a larger cervical barrier, also held in place by suction. The diaphragm fits into place behind the woman's pubic bone and has a firm but flexible ring, which helps it press against the vaginal walls.
The SILCS diaphragm is a new diaphragm design which is still in clinical testing and is not yet available.

Barrier methods
There are variety of delivery methods for hormonal contraception.
Combinations of synthetic oestrogens and progestins (synthetic progestogens) are commonly used. These include the combined oral contraceptive pill ("The Pill"), the Patch, and the contraceptive vaginal ring ("NuvaRing"). Not currently available for sale in the United States is Lunelle, a monthly injection.
Other methods contain only a progestin (a synthetic progestogen). These include the progestin only pill (the POP or 'minipill'), the injectables Depo Provera (a depot formulation of medroxyprogesterone acetate given as an intramuscular injection every three months) and Noristerat (norethisterone acetate given as an intramuscular injection every 8 weeks), and contraceptive implants. The progestin-only pill must be taken at more precisely remembered times each day than combined pills. The first contraceptive implant, the original 6-capsule Norplant, was removed from the market in the United States in 1999, though a newer single-rod implant called Implanon was approved for sale in the United States on July 17, 2006. The various progestin-only methods may cause irregular bleeding during use.

Hormonal methods
Ormeloxifene (Centchroman) is a selective oestrogen receptor modulator, or SERM. It causes ovulation to occur asynchronously with the formation of the uterine lining, preventing implantation of a zygote. It has been widely available as a birth control method in India since the early 1990s, marketed under the trade name Saheli. Centchroman is legally available only in India.

Ormeloxifene (Centchroman)
These are contraceptive devices which are placed inside the uterus. They are usually shaped like a "T" — the arms of the T hold the device in place. There are two main types of intrauterine contraceptives: those that contain copper (which has a spermicidal effect), and those that release a progestogen (in US the term progestin used).
The terminology used for these devices differs in the United Kingdom and the United States. In the US, all devices which are placed in the uterus to prevent pregnancy are referred to as Intra-Uterine Devices (IUDs). In the UK, only copper-containing devices are called IUDs, and hormonal intrauterine contraceptives are referred to with the term Intra-Uterine System (IUS). This may be because there are seven types of copper IUDs available in the UK, compared to only one in the US.

Intrauterine methods
See also: Emergency contraceptive availability by country
Some combined pills and POPs may be taken in high doses to prevent pregnancy after a birth control failure (such as a condom breaking) or after unprotected sex. Hormonal emergency contraception is also known as the "morning after pill," although it is licensed for use up to three days after intercourse.
Copper intrauterine devices may also be used as emergency contraception. For this use, they must be inserted within five days of the birth control failure or unprotected intercourse.
Because emergency contraception may prevent a fertilized egg from developing, some people consider it a form of abortion.

Emergency contraception
Abortion can be done with surgical methods, usually suction-aspiration abortion (in the first trimester) or dilation and evacuation (in the second trimester). Medical abortion uses drugs to end a pregnancy and is approved for pregnancies where the length of gestation has not exceeded 8 weeks.
Some herbs are believed to cause abortion (abortifacients). Peer-reviewed research has proven the efficacy of some of these substances, but the use of herbs to induce abortion is not recommended, due to the risk of serious side effects.
Abortion is subject to ethical debate.

Induced abortion
Surgical sterilization is available in the form of tubal ligation for women and vasectomy for men. In women, the process may be referred to as "tying the tubes," but the fallopian tubes may be tied, cut, clamped, or blocked. This serves to prevent sperm from joining the unfertilized egg. The non-surgical sterilization procedure, Essure, is an example of a procedure that blocks the tubes. Sterilization should be considered permanent.

Sterilization

Behavioral methods
Fertility awareness (FA) methods involve a woman's observation and charting of one or more of her body's primary fertility signs, to determine the fertile and infertile phases of her cycle. Charting may be done by the woman on paper, with the assistance of software, or by fertility monitoring devices that accept and interpret temperature readings, information from home urinalysis tests, or both.
Unprotected sex is restricted to the least fertile period. During the most fertile period, barrier methods may be availed, or she may abstain from intercourse. Most methods track one or more of the three primary fertility signs: changes in basal body temperature, in cervical mucus, and in cervical position, though cervical position is most frequently used as a cross-reference with one or both of the others. If a woman tracks both basal body temperature and another primary sign, the method is referred to as symptothermal. Some fertility monitoring devices use urinalysis to follow the levels of estrogen and luteinizing hormone throughout a woman's menstrual cycle. Other bodily cues such as mittelschmerz are considered secondary indicators.
The term natural family planning (NFP) is sometimes used to refer to any use of FA methods. However, this term specifically refers to the practices which are permitted by the Roman Catholic Church — breastfeeding infertility, and periodic abstinence during fertile times. FA methods may be used by NFP users to identify these fertile times.

Fertility awareness methods
Statistical methods such as the Rhythm Method and Standard Days Method are dissimilar from observational fertility awareness methods, in that they do not involve the observation or recording of bodily cues of fertility. Instead, statistical methods estimate the likelihood of fertility based on the length of past menstrual cycles. Statistical methods are much less accurate than fertility awareness methods, and are considered by many fertility awareness teachers to have been obsolete for at least 20 years.

Statistical methods
Coitus interruptus (literally "interrupted sex"), also known as the withdrawal method, is the practice of ending sexual intercourse ("pulling out") before ejaculation. The main risk of coitus interruptus is that the man may not make the maneuver in time. Although concern has been raised about the risk of pregnancy from sperm in pre-ejaculate, several small studies have failed to find any viable sperm in the fluid.

Coitus interruptus
The risk of pregnancy from non-vaginal sex, such as outercourse (sex without penetration), anal sex, or oral sex is virtually zero. (A very small risk comes from the possibility of semen leaking onto the vulva (with anal sex) or coming into contact with an object, such as a hand, that later contacts the vulva.) However, with this method, care must be taken to prevent the progression to intercourse.

Avoiding vaginal intercourse
Sexual abstinence is the practice of refraining from all sexual activity.

Abstinence
Most breastfeeding women have a period of infertility after the birth of their child. The lactational amenorrhea method, or LAM, gives guidelines for determining the length of a woman's period of breastfeeding infertility.

Lactational

Methods in development

Praneem is a polyherbal vaginal tablet being studied as a spermicide, and a microbicide active against HIV. For females

Main article: Male contraceptive For males
Modern misconceptions and urban legends have given rise to a great deal of false claims:

The suggestion that douching immediately following intercourse works as a contraceptive is untrue. While it may seem like a sensible idea to try to wash the ejaculate out of the vagina, it is not likely to be effective. Due to the nature of the fluids and the structure of the female reproductive tract – if anything, douching spreads semen further towards the uterus. Some slight spermicidal effect may occur if the douche solution is particularly acidic, but overall it is not scientifically observed to be a reliably effective method.
The suggestion to shake a bottle of Coca-Cola and insert it into the vagina after ejaculation is not a form of birth control, it does not prevent pregnancy, and doing this can also promote candidiasis (yeast infections).
It is a myth that a female cannot become pregnant as a result of the first time she engages in sexual intercourse.
While women are usually less fertile for the first few days of menstruation, Misconceptions
See also the table at: Comparison of birth control methods
Effectiveness is measured by how many women become pregnant using a particular birth control method in the first year of use. Thus, if 100 women use a method that has a 12 percent first-year failure rate, then sometime during the first year of use, 12 of the women should become pregnant.
The most effective methods in typical use are those that do not depend upon regular user action. Surgical sterilization, Depo-Provera, implants, and intrauterine devices (IUDs) all have first-year failure rates of less than one percent for perfect use and typical use.

Effectiveness
Not all methods of birth control offer protection against sexually transmitted infections. Abstinence from all forms of sexual behavior will protect against the sexual transmission of these infections. The male latex condom offers some protection against some of these diseases with correct and consistent use, as does the female condom, although the latter has only been approved for vaginal sex. The female condom may offer greater protection against sexually transmitted infections that pass through skin to skin contact, as the outer ring covers more exposed skin than the male condom, and can be used during anal sex to guard against sexually transmitted infections. However, the female condom can be difficult to use. Frequently a woman can improperly insert it, even if she believes she is using it correctly.

Protection against sexually transmitted infections

Religious and cultural attitudes

Main article: Religious views on birth control Birth control education

Population control
One-child policy
Reproductive Health