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. Methods and intentions typically termed birth control may be considered a pivotal ingredient to 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. Contraception differs from abortion in that the former prevents fertilization, while the latter terminates an already established pregnancy. Methods of birth control which may prevent the implantation of an embryo if fertilization occurs are medically considered to be contraception but characterized by some opponents as abortifacients.
Birth control is a controversial political and ethical issue in many cultures and religions, and although it is generally less controversial than abortion specifically, it is still opposed by many. There are various degrees of opposition, including those who oppose all forms of birth control short of sexual abstinence; those who oppose forms of birth control they deem "unnatural", while allowing natural birth control; and those who support most forms of birth control that prevent fertilisation, but oppose any method of birth control which prevents a fertilized embryo from attaching to the uterus and initiating a pregnancy.
History
Probably the oldest methods of contraception (aside from sexual abstinence) are coitus interruptus, certain barrier methods, and herbal methods (emmenagogues and abortifacients).
Coitus interruptus (withdrawal of the penis from the vagina prior to ejaculation) probably predates any other form of birth control. Once the relationship between the emission of semen into the vagina and pregnancy was known or suspected, some men began to use this technique. This is not a particularly reliable method of contraception, as few men have the self-control to correctly practice the method at every single act of intercourse. Although it is commonly believed that pre-ejaculate fluid can cause pregnancy, modern research has shown that pre-ejaculate fluid does not contain viable sperm.
There are historic records of Egyptian women using a pessary (a vaginal suppository) made of various acidic substances (crocodile dung is alleged) and lubricated with honey or oil, which may have been somewhat effective at killing sperm. However, it is important to note that the sperm cell was not discovered until Anton van Leeuwenhoek invented the microscope in the late seventeenth century, so barrier methods employed prior to that time could not know of the details of conception. Asian women may have used oiled paper as a cervical cap, and Europeans may have used beeswax for this purpose. The condom appeared sometime in the seventeenth century, initially made of a length of animal intestine. It was not particularly popular, nor as effective as modern latex condoms, but was employed both as a means of contraception and in the hopes of avoiding syphilis, which was greatly feared and devastating prior to the discovery of antibiotic drugs.
Various abortifacients have been used throughout human history, although many do not associate induced abortion with the term 'birth control'. Some of them were effective, some were not; those that were most effective also had major side effects. One abortifacient reported to have low levels of side effects—silphium—was harvested to extinction around the 1st century. The ingestion of certain poisons by the female can disrupt the reproductive system; women have drunk solutions containing mercury, arsenic, or other toxic substances for this purpose. The Greek gynaecologist Soranus in the 2nd century suggested that women drink water that blacksmiths had used to cool metal. The herbs tansy and pennyroyal are well-known in folklore as abortive agents, but these also "work" by poisoning the woman. Levels of the active chemicals in these herbs that will induce a miscarriage are high enough to damage the liver, kidneys, and other organs, making them very dangerous. However, in those times where risk of maternal death from postpartum complications was high, the risks and side effects of toxic medicines may have seemed less onerous. Some herbalists claim that black cohosh tea will also be effective in certain cases as an abortifacient.
The fact that various effective methods of birth control were known in the ancient world sharply contrasts with a seeming ignorance of these methods in wide segments of the population of early modern Christian Europe. This ignorance continued far into the 20th century, and was paralleled by eminently high birth rates in European countries during the 18th and 19th centuries.. Some historians have attributed this to a series of coercive measures enacted by the emerging modern state, in an effort to repopulate Europe after the population catastrophe of the Black Death, starting in 1348. According to this view, the witch hunts were the first measure the modern state took in an attempt to eliminate knowledge about birth control within the population, and monopolize it in the hands of state-employed male medical specialists (gynecologists). Prior to the witch hunts, male specialists were unheard-of, because birth control was naturally a female domain.
Presenters at a family planning conference told a tale of Arab traders inserting small stones into the uteruses of their camels in order to prevent pregnancy, a concept very similar to the modern IUD. Although the story has been repeated as truth, it has no basis in history and was meant only for entertainment purposes. The first interuterine devices (which occupied both the vagina and the uterus) were first marketed around 1900. The first modern intrauterine device (contained entirely in the uterus) was described in a German publication in 1909, although the author appears to have never marketed his product.
The Rhythm Method (with a rather high method failure rate of 10% per year) was developed in the early twentieth century, as researchers discovered that a woman only ovulates once per menstrual cycle. Not until the mid-20th century, when scientists better understood the functioning of the menstrual cycle and the hormones that controlled it, were oral contraceptives and modern methods of fertility awareness (also called natural family planning) developed.
Methods
- See also: Comparison of birth control methods
Physical methods
Barrier 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 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 contraceptive sponge has a depression to hold it in place over the cervix.
Hormonal methods
There are variety of delivery methods for hormonal contraception.
Combinations of synthetic estrogens 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 while being used.
Ormeloxifene (Centchroman)
Ormeloxifene (Centchroman) is a Selective Estrogen 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 90s, marketed under the trade name Saheli®. Centchroman is legally available only in India.
Intrauterine methods
These are devices that are placed in the uterus. They are usually shaped like a "T"—the arms of the T hold the device in place inside the uterus. In the United States, all devices which are placed in the uterus to prevent pregnancy are referred to as IUDs. In the UK, a distinction is made between the IUDs and IUS. This is probably because there are seven different kinds of IUDs available in the UK, compared to two in the US.
Intrauterine Devices ("IUDs") contain copper (which has a spermicidal effect).
IntraUterine Systems ("IUS") release a progestogen (either progesterone or a progestin).
Emergency contraception
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 intercourse. 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.
Induced abortion
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 of less than 8 weeks gestation.
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.
Sterilization
Surgical sterilization is available in the form of tubal ligation for women and vasectomy for men.
A non-surgical sterilization procedure, Essure, is also available for women.
Behavioral methods
Fertility awareness 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. 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. Different methods track one or more of the three primary fertility signs: basal body temperature, cervical mucus, and cervical position. Other bodily cues including mittelschmerz are considered secondary indicators. A woman may chart these events on paper or with software. FA is versatile and may also be practiced to achieve pregnancy, by identifying the fertile period and having intercourse prior to and during that time.
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.
Statistical 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 twenty years.
Coitus interruptus
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.
Avoiding vaginal intercourse
The risk of pregnancy from non-vaginal sex, such as outercourse (sex without penetration), anal sex, or oral sex is low. (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, discipline is required to prevent the progression to intercourse.
Abstinence
Sexual abstinence is the practice of refraining from all sexual activity. As with avoiding intercourse, the intention to remain abstinent may not prevent pregnancy, due to the level of discipline required.
Lactational
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.
