Birth control

2007 Schools Wikipedia Selection. Related subjects: Health and medicine

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.

Presenters at a family planning conference told a tale of Arab traders inserting small stones into the uteruses of their camel 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

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 estrogen and progestins (synthetic forms of progesterone) 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 is Lunelle, a monthly injection.

Other methods contain only progesterone, or a progestin. These include the progesterone only pill (the POP or 'minipill'), and Depo Provera ( medroxyprogesterone acetate) given as an intramuscular injection every three months, and Noristerat ( norethisterone acetate), which is given as an intramuscular injection every 8 weeks. The progesterone-only pill must be taken at more precisely remembered times each day than combined pills. A contraceptive implant called Norplant was removed from the market in 2002, though a newer implant called Implanon was approved for sale on July 17, 2006. The various progesterone-only methods may cause irregular bleeding for several months.

Centchroman

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®. It is not legally available anywhere outside of India, and it is not in the process of becoming available in the United States.

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 progesterone or a progestin.

Emergency contraception

Most 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). Chemical abortion uses drugs to end a pregnancy and is approved for pregnancies of less than 7 weeks gestation. Later-term abortions may use prostaglandins to induce premature delivery. An injection to stop the fetal heart may be used prior to induction.

Some herbs are believed to cause abortion ( abortifacients). No peer-reviewed research has been done on these substances.

The use of abortion as birth control is a controversial issue, 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.

Behavioural 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. Primary methods of determining fertility include monitoring of basal body temperature and of cervical mucus, while cervical position and 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 describe any use of FA methods. However, this term specifically refers to a set of several birth control methods approved by the Roman Catholic Church. Research by Catholics resulted in the Billings ovulation method and the Creighton Model, two types of FA which are promoted as natural family planning. Although the physical methods used in these kinds of NFP and those used in FA are identical, NFP involves additional behaviour restrictions defined by Catholic beliefs. These restrictions are not specific to the practice of FA.

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. The Rhythm Method is much less accurate than fertility awareness methods, and is considered by 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 is low, such as outercourse (sex without penetration), anal sex, or oral sex. With this method, great discipline is required from both partners to prevent the progression to intercourse. Due to the level of discipline required while in a passionate state, this method may be considered unreliable, and the potential to progress to intercourse should be addressed with physical precautions.

Abstinence

Sexual abstinence (also known as celibacy), is the practice of avoiding all sexual activity. It is highly effective if practiced consistently. As with avoiding intercourse, however, it may be unreliable due to the level of discipline required. This method cannot be considered perfect or infallible, because a fertile woman who practices abstinence alone can still become pregnant if she is raped.

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.

Methods in development

Experimental contraceptives for males

Research is being done into a variety of substances that have potential as male oral contraceptives, or implants or injections that may be used as male hormonal contraceptives.

RISUG (Reversible Inhibition of Sperm Under Guidance), is an injection into the vas deferens that coats the walls of the vas with a spermicidal substance. This method can be reversed by washing out the vas deferens with a second injection.

Vas-occlusive contraception would be analogous to intrauterine contraception in women.

Heat-based contraception involves heating the testicles to a high temperature for a short period of time.

Myths

Modern myths 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 does not work. 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 get pregnant the first time she engages in sexual intercourse.
• While women are usually less fertile for the first few days of menstruation, it is a myth that a woman cannot get pregnant if she has sex during her period.
• Having sex in a hot tub does not prevent pregnancy, but may contribute to vaginal infections.
• Although some sex positions may encourage pregnancy, no sexual positions prevent pregnancy. Having sex while standing up or with a woman on top will not keep the sperm from entering the uterus. The force of ejaculation and the ability of sperm to swim overrides gravity.
• Sneezing or urinating after sex are also completely ineffective, they do not prevent pregnancy and are not forms of birth control.
• Toothpaste cannot be used as an effective contraceptive

Effectiveness

Effectiveness is measured by how many women become pregnant using a particular birth control method in a year. Thus, if 100 women use a method that has a 12% failure rate, sometime during that year, 12 of the women will become pregnant.

The most effective methods in typical use are those that do not depend upon regular user action. Surgical sterilization, Depo-Provera, and intrauterine devices (IUDs) all have failure rates of less than 1% per year for perfect use. Depo-Provera, or the shot, has a typical failure rate of 3%, while sterilization and IUD's still have a typical failure use under 1%.

Other methods may be highly effective if used consistently and correctly, but can have typical use failure rates that are considerably lower due to incorrect or ineffective usage by the user. Hormonal contraceptives, fertility awareness methods, and ecological breastfeeding, if used strictly, have failure rates of less than 1% per year. Typical use failure rates of hormonal contraceptives are as high as 8% per year. Fertility awareness methods as a whole have typical-use failure rates as high as 25% per year; however, as stated above, perfect use of these methods reduces the failure rate to less than 1%.

Condoms and cervical barriers such as the diaphragm have similar typical use failure rates (15.0% and 16%, respectively), but perfect usage of the condom is more effective (2% failure vs 6%) and condoms have the additional feature of helping to prevent the spread of sexually transmitted diseases such as HIV. The withdrawal method, if used consistently and correctly, has a failure rate of 4%. Due to the difficulty of consistently using withdrawal correctly, it has a typical use failure rate of 27% and is not recommended by some medical professionals, although others believe it deserves more support.

Protection against sexually transmitted infections

Not all methods of birth control offer protection against sexually transmitted infections. Abstinence from all forms of sexual behaviour 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. Freqently a woman can improperly insert it, even if she believes she is using it correctly.

The remaining methods of birth control do not offer significant protection against the sexual transmission of these diseases.

However, so-called sexually transmitted infections may also be transmitted non-sexually, and therefore, abstinence from sexual behaviour does not guarantee 100% protection against sexually transmitted infections. For example, HIV may be transmitted through contaminated needles which may be used in tattooing, body piercing, or injections. Health-care workers have acquired HIV through occupational exposure to accidental injuries with needles.

Religious and cultural attitudes

Religious views on birth control

Religions vary widely in their views of the ethics of birth control. In Christianity, the Roman Catholic Church accepts only Natural Family Planning, while Protestants maintain a wide range of views from allowing none to very lenient. Views in Judaism range from the stricter Orthodox sect to the more relaxed Reformed sect. In Islam, contraceptives are allowed if they do not threaten health or lead to sterilty, although their use is sometimes discouraged. Hindus may use both natural and artificial contraceptives.

Birth control education

Many teenagers, most commonly in developed countries, receive some form of sex education in school. What information should be provided in such programs is hotly contested, especially in the United States and Great Britain. Possible topics include reproductive anatomy, human sexual behaviour, information on sexually transmitted diseases (STDs), social aspects of sexual interaction, negotiating skills intended to help teens follow through with a decision to remain abstinent or to use birth control during sex, and information on birth control methods.

One type of sex education program, called abstinence-only education, promotes abstinence until marriage and does not provide information on birth control, or heavily emphasizes negative information such as failure rates. Because abstinence offers better protection against pregnancy and disease than sexual activity with even the best birth control methods, advocates of abstinence-only education believe they will result in decreased rates of teenage pregnancy and STD infection. However, some studies have found that abstinence-only sex education programs actually increase the rates of pregnancy and STDs in the teenage population.