Early spontaneous abortion (the most prevalent) is usually due to fetal malformations or chromosomal abnormalities. Spontaneous abortion during the last two thirds of pregnancy is more likely to be due to maternal factors, for example abnormalities of the cervix or uterus, insufficient progesterone, sexually transmitted diseases that affect the genital tract, endocrine dysfunction (as in hypothyroidism and diabetes mellitus), or severe emotional trauma. Immunological reactions, in which maternal antibodies mistake the fetus for foreign tissue, have been implicated in recurrent, or habitual spontaneous abortions. It is estimated that at least 20% of all pregnancies end in miscarriage (estimates range from 15% to 75%). Most occur in the first two weeks after conception, and in many cases the mother is not aware of the pregnancy.
Abortion can be induced for medical reasons or because of an elective decision to end the pregnancy. Procedures for inducing abortion include vacuum suction (the most common, used in the early stages of pregnancy), dilatation and evacuation (D and E), induction (injection of abortifacients such as prostaglandins into the uterus), and hysterotomy (a surgical procedure similar to a cesarean section, used later in pregnancy, especially when the woman's life is in danger). The "abortion pill," the drug RU-486 (mifepristone), was approved by the Food and Drug Administration in the United States in 2000. It is used within the first seven weeks of pregnancy. A second drug is taken two days later to start uterine contractions and complete the abortion. The drugs methotrexate and misoprostol have also been used experimentally to end early pregnancies.
Abortion induced by herbs or manipulation was used as a form of birth control in ancient Egypt, Greece, and Rome and probably earlier. In the Middle Ages in Western Europe it was generally accepted in the early months of pregnancy. However, in the 19th cent. opinion about abortion changed. In 1869 the Roman Catholic Church prohibited abortion under any circumstances. In England and in the United States in the 19th cent. stringent antiabortion laws were passed.
Attitudes toward abortion became more liberal in the 20th cent. By the 1970s, abortion had been legalized in most European countries and Japan; in the United States, under a 1973 Supreme Court ruling (see Roe v. Wade), abortions are permitted during the first six months of pregnancy. Abortion remains a controversial issue in the United States, however, and in 1977 Congress barred the use of Medicaid funds for abortion except for therapeutic reasons and in certain other specified instances. Several state legislatures passed restrictive abortion laws in hope that the Supreme Court would overturn Roe v. Wade, but in 1992 the court reaffirmed the basic principles of the 1973 decision.
From 1995 to 2000 the U.S. Congress repeatedly passed, but President Bill Clinton vetoed, a bill that would ban a rare late-term method of abortion called by its critics "partial-birth abortion." Subsequent attempts by many U.S. states to ban this method were contested in the courts, and in 2000 the Supreme Court voided such laws that do not include an exception when the health of the mother is endangered. A federal bill banning banning the procedure was passed again in 2003 and signed into law by President George W. Bush. The law was quickly challenged in the courts, and a federal judge declared it unconstitutional in 2004 in part because of its lack of a health exception, but the Supreme Court, with two new conservative members appointed by President Bush, upheld the law in 2007. U.S. opponents of abortion have used more militant tactics at times in attempts to disrupt the operations of facilities that perform abortions, and some extremists have resorted to bombings and assassination. In India, the abortion of female fetuses by couples desiring a male child led (1994) to criminal penalties for prenatal testing when done solely to determine the sex of the fetus; such tests have been banned in parts of China for the same reason.
See M. Muldoon, The Abortion Debate in the United States and Canada: A Source Book (1991); J. M. Riddle, Contraception and Abortion from the Ancient World to the Renaissance (1994); Boston Women's Health Book Collective, Our Bodies, Ourselves for the New Century (1998); J. Risen and J. L. Thomas, Wrath of Angels (1998).
Spontaneous expulsion of an embryo or fetus from the uterus before it can live outside the mother. More than 60percnt are caused by an inherited defect in the fetus, which might result in a fatal abnormality. Other causes may include acute infectious disease, especially if it reduces the fetus's oxygen supply; abnormalities of the uterus that have physical or hormonal origins; and death of the fetus from umbilical-cord knotting. The main sign of impending miscarriage is vaginal bleeding.
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Expulsion of a fetus from the uterus before it can survive on its own. Spontaneous abortion at earlier stages of pregnancy is called miscarriage. Induced abortions often occur through intentional medical intervention and are performed to preserve the woman’s life or health, to prevent the completion of a pregnancy resulting from rape or incest, to prevent the birth of a child with serious medical problems, or because the woman does not believe she is in a position to rear a child properly. The drug RU-486, if taken within a few weeks of conception, will trigger a miscarriage. Up to about 19 weeks of pregnancy, injections of saline solutions or hormones may be used to stimulate uterine contractions that will expel the fetus. Surgical removal of the contents of the uterus may be performed in the second trimester or later. Intact dilation and extraction procedures may occur in the third trimester; sometimes critically referred to as “partial-birth abortions,” they have been very controversial. Other abortion procedures include manual vacuum aspiration (extraction by manual syringe) and dilation and suction curettage (extraction by machine-operated suction), both of which can be performed in early pregnancy. The social acceptability of abortion as a means of population control has varied from time to time and place to place throughout history. It was apparently a common method of family limitation in the Greco-Roman world, but Christian theologians early and vehemently condemned it. It became widely accepted in Europe in the Middle Ages. Severe criminal sanctions to deter abortion became common in the 19th century, but in the 20th century those sanctions were gradually modified in many countries. In the U.S. the 1973
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Abortion has a long history and has been induced by various methods including herbal abortifacients, the use of sharpened tools, physical trauma and other traditional methods. Modern medicine utilizes medications and surgical procedures to induce abortion. The legality, prevalence, and cultural views on abortion vary substantially around the world. In many parts of the world there is intense public debate over the ethical and legal aspects of abortion. The approximate number of induced abortions performed worldwide in 2003 was 42 million, which declined from nearly 46 million in 1995.
Spontaneous abortion (also known as miscarriage) is the expulsion of an embryo or fetus due to accidental trauma or natural causes. Most miscarriages are due to incorrect replication of chromosomes; they can also be caused by environmental factors. Spontaneous abortions, generally referred to as miscarriages, occur when an embryo or fetus is lost due to natural causes before the 20th week of gestation. A pregnancy that ends between 20 and 37 weeks of gestation, if it results in a live-born infant, is known as a "premature birth". When a fetus dies in utero after about 20 weeks, or during delivery, it is termed "stillborn". Premature births and stillbirths are generally not considered to be miscarriages although usage of these terms can sometimes overlap.
Most miscarriages occur very early in pregnancy. Between 10% and 50% of pregnancies end in clinically apparent miscarriage, depending upon the age and health of the pregnant woman. In most cases, they occur so early in the pregnancy that the woman is not even aware that she was pregnant. One study testing hormones for ovulation and pregnancy showed a rate of pregnancy in exposed ovulatory cycles of 59.6%; with 61.9% of conceptuses lost prior to 12 weeks of which 91.7% occuried subclinically, without the knowledge of the mother.
The risk of spontaneous abortion decreases sharply after the 10th week from the last menstrual period (LMP), with a loss rate between 8.5 weeks LMP and birth of about two percent; pregnancy loss is “virtually complete by the end of the embryonic period.
This risk of spontaneous abortion is greater in those with a known history of several spontaneous abortions or an induced abortion, those with systemic diseases, and those over the age 35. Other causes can be infection (of either the woman or fetus), immune response, or serious systemic disease. A spontaneous abortion can also be caused by accidental trauma; intentional trauma or stress to cause miscarriage is considered induced abortion or feticide.
Any abortion that is not therapeutic is by definition elective.
In the first 12 weeks, suction-aspiration or vacuum abortion is the most common method. Manual Vacuum aspiration (MVA) abortion consists of removing the fetus or embryo by suction using a manual syringe, while electric vacuum aspiration (EVA) abortion uses an electric pump. These techniques are comparable, and differ in the mechanism used to apply suction, how early in pregnancy they can be used, and whether cervical dilation is necessary. MVA, also known as "mini-suction" and "menstrual extraction", can be used in very early pregnancy, and does not require cervical dilation. Surgical techniques are sometimes referred to as 'Suction (or surgical) Termination Of Pregnancy' (STOP). From the 15th week until approximately the 26th, dilation and evacuation (D&E) is used. D&E consists of opening the cervix of the uterus and emptying it using surgical instruments and suction.
Dilation and curettage (D&C), the second most common method of abortion, is a standard gynecological procedure performed for a variety of reasons, including examination of the uterine lining for possible malignancy, investigation of abnormal bleeding, and abortion. Curettage refers to cleaning the walls of the uterus with a curette. The World Health Organization recommends this procedure, also called sharp curettage, only when MVA is unavailable. The term D and C, or sometimes suction curette, is used as a euphemism for the first trimester abortion procedure, whichever the method used.
Other techniques must be used to induce abortion in the second trimester. Premature delivery can be induced with prostaglandin; this can be coupled with injecting the amniotic fluid with caustic solutions containing saline or urea. After the 16th week of gestation, abortions can be induced by intact dilation and extraction (IDX) (also called intrauterine cranial decompression), which requires surgical decompression of the fetus' head before evacuation. IDX is sometimes called "partial-birth abortion," which has been federally banned in the United States. A hysterotomy abortion is a procedure similar to a caesarean section, and is performed under general anesthesia because it is considered major abdominal surgery. It requires a smaller incision than a caesarean section and is used during later stages of pregnancy.
Effective in the first trimester of pregnancy, non-surgical abortions (referred to as 'medical abortions') comprise 10% of all abortions in the United States and Europe. Combined regimens include methotrexate or mifepristone, followed by a prostaglandin (either misoprostol or gemeprost: misoprostol is used in the U.S.; gemeprost is used in the UK and Sweden.) When used within 49 days gestation, approximately 92% of women undergoing medical abortion with a combined regimen completed it without surgical intervention. Misoprostol can be used alone, but has a lower efficacy rate than combined regimens. In cases of failure of medical abortion, vacuum or manual aspiration is used to complete the abortion surgically.
Abortion is sometimes attempted by causing trauma to the abdomen. The degree of force, if severe, can cause serious internal injuries without necessarily succeeding in inducing miscarriage. Both accidental and deliberate abortions of this kind can be subject to criminal liability in many countries. In Burma, Indonesia, Malaysia, the Philippines, and Thailand, there is an ancient tradition of attempting abortion through forceful abdominal massage.
Reported methods of unsafe, self-induced abortion include misuse of misoprostol, and insertion of non-surgical implements such as knitting needles and clothes hangers into the uterus. These methods are rarely seen in developed countries where surgical abortion is legal and available.
Women typically experience minor pain during first-trimester abortion procedures. In a 1979 study of 2,299 patients, 97% reported experiencing some degree of pain. Patients rated the pain as being less than earache or toothache, but more than headache or backache.
Local and general anesthetics are used during the procedure
In a 1990 review, the American Psychological Association (APA) found that "severe negative reactions [after abortion] are rare and are in line with those following other normal life stresses. The APA revised and updated its findings in August 2008 to account for the accumulation of new evidence, and again concluded that induced abortion did not lead to increased mental health problems. As of August 2008, the United Kingdom Royal College of Psychiatrists is also performing a systematic review of the medical literature to update their position statement on the subject.
Some proposed negative psychological effects of abortion have been referred to by pro-life advocates as a separate condition called "post-abortion syndrome." However, the existence of "post-abortion syndrome" is not recognized by any medical or psychological organization, and some physicians and pro-choice advocates have argued that the effort to popularize the idea of a "post-abortion syndrome" is a tactic used by pro-life advocates for political purposes.
Abortion rates also vary depending on the stage of pregnancy and the method practiced. In 2003, from data collected in those areas of the United States that sufficiently reported gestational age, it was found that 88.2% of abortions were conducted at or prior to 12 weeks, 10.4% from 13 to 20 weeks, and 1.4% at or after 21 weeks. 90.9% of these were classified as having been done by "curettage" (suction-aspiration, Dilation and curettage, Dilation and evacuation), 7.7% by "medical" means (mifepristone), 0.4% by "intrauterine instillation" (saline or prostaglandin), and 1.0% by "other" (including hysterotomy and hysterectomy). The Guttmacher Institute estimated there were 2,200 intact dilation and extraction procedures in the U.S. during 2000; this accounts for 0.17% of the total number of abortions performed that year. Similarly, in England and Wales in 2006, 89% of terminations occurred at or under 12 weeks, 9% between 13 to 19 weeks, and 1.5% at or over 20 weeks. 64% of those reported were by vacuum aspiration, 6% by D&E, and 30% were medical.
A 1998 aggregated study, from 27 countries, on the reasons women seek to terminate their pregnancies concluded that common factors cited to have influenced the abortion decision were: desire to delay or end childbearing, concern over the interruption of work or education, issues of financial or relationship stability, and perceived immaturity. A 2004 study in which American women at clinics answered a questionnaire yielded similar results. In Finland and the United States, concern for the health risks posed by pregnancy in individual cases was not a factor commonly given; however, in Bangladesh, India, and Kenya health concerns were cited by women more frequently as reasons for having an abortion. 1% of women in the 2004 survey-based U.S. study became pregnant as a result of rape and 0.5% as a result of incest. Another American study in 2002 concluded that 54% of women who had an abortion were using a form of contraception at the time of becoming pregnant while 46% were not. Inconsistent use was reported by 49% of those using condoms and 76% of those using the combined oral contraceptive pill; 42% of those using condoms reported failure through slipping or breakage. The Guttmacher Institute estimated that "most abortions in the United States are obtained by minority women" because minority women "have much higher rates of unintended pregnancy.
Some abortions are undergone as the result of societal pressures. These might include the stigmatization of disabled persons, preference for children of a specific sex, disapproval of single motherhood, insufficient economic support for families, lack of access to or rejection of contraceptive methods, or efforts toward population control (such as China's one-child policy). These factors can sometimes result in compulsory abortion or sex-selective abortion.
Induced abortion can be traced to ancient times. There is evidence to suggest that, historically, pregnancies were terminated through a number of methods, including the administration of abortifacient herbs, the use of sharpened implements, the application of abdominal pressure, and other techniques.
The Hippocratic Oath, the chief statement of medical ethics for Hippocratic physicians in Ancient Greece, forbade doctors from helping to procure an abortion by pessary. Soranus, a second-century Greek physician, suggested in his work Gynaecology that women wishing to abort their pregnancies should engage in energetic exercise, energetic jumping, carrying heavy objects, and riding animals. He also prescribed a number of recipes for herbal baths, pessaries, and bloodletting, but advised against the use of sharp instruments to induce miscarriage due to the risk of organ perforation. It is also believed that, in addition to using it as a contraceptive, the ancient Greeks relied upon silphium as an abortifacient. Such folk remedies, however, varied in effectiveness and were not without risk. Tansy and pennyroyal, for example, are two poisonous herbs with serious side effects that have at times been used to terminate pregnancy.
Abortion in the 19th century continued, despite bans in both the United Kingdom and the United States, as the disguised, but nonetheless open, advertisement of services in the Victorian era suggests.
In the 20th century the Soviet Union (1919), Iceland (1935) and Sweden (1938) were among the first countries to legalize certain or all forms of abortion. In 1935 Nazi Germany, a law was passed permitting abortions for those deemed "hereditarily ill", while women considered of German stock were specifically prohibited from having abortions.
The advent of both sonography and amniocentesis has allowed parents to determine sex before birth. This has led to the occurrence of sex-selective abortion or the targeted termination of a fetus based upon its sex.
It is suggested that sex-selective abortion might be partially responsible for the noticeable disparities between the birth rates of male and female children in some places. The preference for male children is reported in many areas of Asia, and abortion used to limit female births has been reported in Mainland China, Taiwan, South Korea, and India.
In India, the economic role of men, the costs associated with dowries, and a Hindu tradition which dictates that funeral rites must be performed by a male relative have led to a cultural preference for sons. The widespread availability of diagnostic testing, during the 1970s and '80s, led to advertisements for services which read, "Invest 500 rupees [for a sex test] now, save 50,000 rupees [for a dowry] later. In 1991, the male-to-female sex ratio in India was skewed from its biological norm of 105 to 100, to an average of 108 to 100. Researchers have asserted that between 1985 and 2005 as many as 10 million female fetuses may have been selectively aborted. The Indian government passed an official ban of pre-natal sex screening in 1994 and moved to pass a complete ban of sex-selective abortion in 2002.
In the People's Republic of China, there is also a historic son preference. The implementation of the one-child policy in 1979, in response to population concerns, led to an increased disparity in the sex ratio as parents attempted to circumvent the law through sex-selective abortion or the abandonment of unwanted daughters. Sex-selective abortion might be an influence on the shift from the baseline male-to-female birth rate to an elevated national rate of 117:100 reported in 2002. The trend was more pronounced in rural regions: as high as 130:100 in Guangdong and 135:100 in Hainan. A ban upon the practice of sex-selective abortion was enacted in 2003.
Where and when access to safe abortion has been barred, due to explicit sanctions or general unavailability, women seeking to terminate their pregnancies have sometimes resorted to unsafe methods.
The World Health Organization (WHO) defines an unsafe abortion as being "a procedure...carried out by persons lacking the necessary skills or in an environment that does not conform to minimal medical standards, or both." Unsafe abortions are known colloquially as "back-alley abortions. This can include a person without medical training, a professional health provider operating in sub-standard conditions, or the woman herself.
Unsafe abortion remains a public health concern today due to the higher incidence and severity of its associated complications, such as incomplete abortion, sepsis, hemorrhage, and damage to internal organs. WHO estimates that 19 million unsafe abortions occur around the world annually and that 68,000 of these result in the woman's death. Complications of unsafe abortion are said to account, globally, for approximately 13% of all maternal mortalities, with regional estimates including 12% in Asia, 25% in Latin America, and 13% in sub-Saharan Africa. A 2007 study published in the The Lancet found that, although the global rate of abortion declined from 45.6 million in 1995 to 41.6 million in 2003, unsafe procedures still accounted for 48% of all abortions performed in 2003. Health education, access to family planning, and improvements in health care during and after abortion have been proposed to address this phenomenon.
In the history of abortion, induced abortion has been the source of considerable debate, controversy, and activism. An individual's position on the complex ethical, moral, philosophical, biological, and legal issues is often related to his or her value system. Opinions of abortion may be best described as being a combination of beliefs on its morality, and beliefs on the responsibility, ethical scope, and proper extent of governmental authorities in public policy. Religious ethics also has an influence upon both personal opinion and the greater debate over abortion (see religion and abortion).
Abortion debates, especially pertaining to abortion laws, are often spearheaded by advocacy groups belonging to one of two camps. In the United States, most often those in favor of greater legal restrictions on, or even complete prohibition of abortion, describe themselves as pro-life while those against legal restrictions on abortion describe themselves as pro-choice. Both are used to indicate the central principles in arguments for and against abortion: "Is the fetus a human being with a fundamental right to life?" for pro-life advocates, and, for those who are pro-choice, "Does a woman have the right to choose whether or not to continue a pregnancy?"
In both public and private debate, arguments presented in favor of or against abortion focus on either the moral permissibility of an induced abortion, or justification of laws permitting or restricting abortion. Arguments on morality and legality tend to collide and combine, complicating the issue at hand.
Debate also focuses on whether the pregnant woman should have to notify and/or have the consent of others in distinct cases: a minor, her parents; a legally-married or common-law wife, her husband; or a pregnant woman, the biological father. In a 2003 Gallup poll in the United States, 79% of male and 67% of female respondents were in favor of spousal notification; overall support was 72% with 26% opposed.
A number of opinion polls around the world have explored public opinion regarding the issue of abortion. Results have varied from poll to poll, country to country, and region to region, while varying with regard to different aspects of the issue.
A May 2005 survey examined attitudes toward abortion in 10 European countries, asking polltakers whether they agreed with the statement, "If a woman doesn't want children, she should be allowed to have an abortion". The highest level of approval was 81% (in the Czech Republic); the lowest was 47% (in Poland).
In North America, a December 2001 poll surveyed Canadian opinion on abortion, asking Canadians in what circumstances they believe abortion should be permitted; 32% responded that they believe abortion should be legal in all circumstances, 52% that it should be legal in certain circumstances, and 14% that it should be legal in no circumstances. A similar poll in January 2006 surveyed people in the United States about U.S. opinion on abortion; 33% said that abortion should be "permitted only in cases such as rape, incest or to save the woman's life", 27% said that abortion should be "permitted in all cases", 15% that it should be "permitted, but subject to greater restrictions than it is now", 17% said that it should "only be permitted to save the woman's life", and 5% said that it should "never" be permitted. A November 2005 poll in Mexico found that 73.4% think abortion should not be legalized while 11.2% think it should.
Of attitudes in South and Central America, a December 2003 survey found that 30% of Argentines thought that abortion in Argentina should be allowed "regardless of situation", 47% that it should be allowed "under some circumstances", and 23% that it should not be allowed "regardless of situation". A March 2007 poll regarding the abortion law in Brazil found that 65% of Brazilians believe that it "should not be modified", 16% that it should be expanded "to allow abortion in other cases", 10% that abortion should be "decriminalized", and 5% were "not sure". A July 2005 poll in Colombia found that 65.6% said they thought that abortion should remain illegal, 26.9% that it should be made legal, and 7.5% that they were unsure.
In early pregnancy, levels of estrogen increase, leading to breast growth in preparation for lactation. The hypothesis proposes that if this process is interrupted by an abortion before full maturity in the third trimester then more relatively vulnerable immature cells could be left than there were prior to the pregnancy, resulting in a greater potential risk of breast cancer. The hypothesis mechanism was first proposed and explored in rat studies conducted in the 1980s.
The American Cancer Society concludes that presently the evidence does not support a causal abortion-breast cancer association, yet some pro-life activists continue to champion a causal link. In the past, pro-life advocates in the United States have sought legal action regarding disclosure of the abortion-breast cancer issue. This brought short-term legal and political intervention culminating with the Bush Administration changing the National Cancer Institute (NCI) fact sheet from concluding no link to a more ambiguous assessment. In February 2003, the NCI responded by conducting a workshop with over 100 experts on the issue, which concluded that it was well-established that "abortion is not associated with an increase in breast cancer risk."
Though the scientific community has found evidence for the hypothesis lacking, the ongoing promotion of an abortion-breast cancer "link" by pro-life advocates and medical associations is seen by others as merely a part of the current pro-life "woman-centered" strategy against abortion. Pro-life groups maintain they are providing legally necessary informed consent; a concern shared by conservative Congressman Dr. Dave Weldon. While early research indicated a correlation between breast cancer and abortion; the current scientific consensus has solidified with the publication of large prospective cohort studies which find no clear association between abortion and breast cancer. These studies along with all relevant research strive to remove from their results the many confounding factors, such as delayed child bearing (parity), which affect breast cancer risk apart from abortion. The abortion-breast cancer hypothesis continues to incite mostly political and some scientific debate.
A review by researchers from the University of California, San Francisco in JAMA concluded that data from dozens of medical reports and studies indicate that fetuses are unlikely to feel pain until the third trimester of pregnancy. There is an emerging consensus among developmental neurobiologists that the establishment of thalamocortical connections (at about 26 weeks) is a critical event with regard to fetal perception of pain. Because pain can involve sensory, emotional and cognitive factors, it may be "impossible to know" when painful experiences are perceived, even if it is known when thalamocortical connections are established.
The suggestion was brought to widespread attention by a 1999 academic paper, The Impact of Legalized Abortion on Crime, authored by the economists Steven D. Levitt and John Donohue. They attributed the drop in crime to a reduction in individuals said to have a higher statistical probability of committing crimes: unwanted children, especially those born to mothers who are African-American, impoverished, adolescent, uneducated, and single. The change coincided with what would have been the adolescence, or peak years of potential criminality, of those who had not been born as a result of Roe v. Wade and similar cases. Donohue and Levitt's study also noted that states which legalized abortion before the rest of the nation experienced the lowering crime rate pattern earlier, and those with higher abortion rates had more pronounced reductions.
Fellow economists Christopher Foote and Christopher Goetz criticized the methodology in the Donohue-Levitt study, noting a lack of accommodation for statewide yearly variations such as cocaine use, and recalculating based on incidence of crime per capita; they found no statistically significant results. Levitt and Donohue responded to this by presenting an adjusted data set which took into account these concerns and reported that the data maintained the statistical significance of their initial paper.
Such research has been criticized by some as being utilitarian, discriminatory as to race and socioeconomic class, and as promoting eugenics as a solution to crime. Levitt states in his book Freakonomics that they are neither promoting nor negating any course of action—merely reporting data as economists.
Before the scientific discovery that human development begins at fertilization, English common law allowed abortions to be performed before "quickening", the earliest perception of fetal movement by a woman during pregnancy, until both pre- and post-quickening abortions were criminalized by Lord Ellenborough's Act in 1803. In 1861, the British Parliament passed the Offences Against the Person Act, which continued to outlaw abortion and served as a model for similar prohibitions in some other nations. The Soviet Union, with legislation in 1920, and Iceland, with legislation in 1935, were two of the first countries to generally allow abortion. The second half of the 20th century saw the liberalization of abortion laws in other countries. The Abortion Act 1967 allowed abortion for limited reasons in the United Kingdom. In the 1973 case, Roe v. Wade, the United States Supreme Court struck down state laws banning abortion, ruling that such laws violated an implied right to privacy in the United States Constitution. The Supreme Court of Canada, similarly, in the case of R. v. Morgentaler, discarded its criminal code regarding abortion in 1988, after ruling that such restrictions violated the security of person guaranteed to women under the Canadian Charter of Rights and Freedoms. Canada later struck down provincial regulations of abortion in the case of R. v. Morgentaler (1993). By contrast, abortion in Ireland was affected by the addition of an amendment to the Irish Constitution in 1983 by popular referendum, recognizing "the right to life of the unborn".
Current laws pertaining to abortion are diverse. Religious, moral, and cultural sensibilities continue to influence abortion laws throughout the world. The right to life, the right to liberty, the right to security of person, and the right to reproductive health are major issues of human rights that are sometimes used as justification for the existence or absence of laws controlling abortion. Many countries in which abortion is legal require that certain criteria be met in order for an abortion to be obtained, often, but not always, using a trimester-based system to regulate the window of legality:
Other countries, in which abortion is normally illegal, will allow one to be performed in the case of rape, incest, or danger to the pregnant woman's life or health. A few nations ban abortion entirely: Chile, El Salvador, Malta, Ireland and Nicaragua, although in 2006 the Chilean government began the free distribution of emergency contraception. In Bangladesh, abortion is illegal, but the government has long supported a network of "menstrual regulation clinics", where menstrual extraction (manual vacuum aspiration) can be performed as menstrual hygiene.
In places where abortion is illegal or carries heavy social stigma, pregnant women may engage in medical tourism and travel to countries where they can terminate their pregnancy. In the USA, it is not unusual for women to travel from one state to another for reasons of termination of pregnancy.
The following information resources may be created by those with a non-neutral position in the abortion debate: