An abortion is the removal or expulsion of an embryo or fetus from the uterus, resulting in or caused by its death. The spontaneous expulsion of a fetus or embryo before the 20th week of gestational age[1] is commonly known as a miscarriage.[2] Induced abortion is the removal or expulsion of an embryo or fetus by medical, surgical, or other means at any point during human pregnancy for therapeutic or elective reasons. The approximate number of induced abortions performed worldwide in 2003 was 42 million.
Throughout recorded history, abortion has been induced by various traditional medicine methods, including botanical abortifacients, the use of sharpened tools, and abdominal pressure.
The moral and legal aspects of abortion are subject to intense social debate in many parts of the world. Aspects of this debate can include the public health impact of unsafe or illegal abortion as well as legal abortion's effect upon crime rates, and the ramifications of sex-selective practices. Other debates include the abortion-breast cancer hypothesis, post-abortion syndrome, and fetal pain. Moral arguments often equate abortion to murder, or denial of abortion to oppression of women.
The history of modern Western abortion laws can be traced back to English common law, which allowed abortion before the "quickening" of the fetus. Currently, abortion law varies from country to country, with regard to religious, moral, and cultural sensibilities.
Forms of abortion
In medical terminology, the term abortion refers to two basic phenomena: miscarriage (spontaneous abortion) and induced abortion. In common parlance, the term "abortion" is synonymous with induced abortion. However, in medical texts, the word 'abortion' might exclusively refer to, or may also refer to, spontaneous abortion (miscarriage).
Spontaneous abortion
Spontaneous abortion 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 a "stillbirth". 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.[5] 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.[6]
The risk of spontaneous abortion decreases sharply after the 10th week LMP,[7] 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."[8]
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 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 to cause miscarriage is considered induced abortion or feticide.[9]
Induced abortion
A pregnancy can be intentionally aborted in many ways. The manner selected depends chiefly upon the gestational age of the embryo or fetus, in addition to the legality, regional availability, and doctor-patient preference for specific procedures. Reasons for procuring induced abortions are typically characterized as either therapeutic or elective. An abortion is considered to be therapeutic when it is performed to:
- to save the life of the pregnant woman;[10]
- to preserve the woman's physical or mental health;[10]
- to terminate pregnancy that would result in a child born with a congenital disorder that would be fatal or associated with significant morbidity;[10] or
- to selectively reduce the number of fetuses to lessen health risks associated with multiple pregnancy.[10]
An abortion is considered to be elective if it is performed for any other reason.
Methods
Surgical
In the first 12 weeks, suction-aspiration or vacuum abortion is the most common method.[11] 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.[12] 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's 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.[13]
From the 20th to 23rd week of gestation, an injection to stop the fetal heart can be used as the first phase of the surgical abortion procedure[14] to ensure that the fetus is not born alive.[15]
Medical
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.[16] 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.
Other means
Historically, a number of herbs reputed to possess abortifacient properties have been used in folk medicine: tansy, pennyroyal, black cohosh, and the now-extinct silphium (see history of abortion).[17] The use of herbs in such a manner can cause serious — even lethal — side effects, such as multiple organ failure, and is not recommended by physicians.[18]
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.[19] 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.[20]
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.[21]
Incidence of induced abortion
The incidence and reasons for induced abortion vary regionally. It has been estimated that approximately 46 million abortions are performed worldwide every year. Of these, 26 million are said to occur in places where abortion is legal; the other 20 million happen where the procedure is illegal. Some countries, such as Belgium (11.2 per 100 known pregnancies) and the Netherlands (10.6 per 100), have a low rate of induced abortion, while others like Russia (62.6 per 100) and Vietnam (43.7 per 100) have a comparatively high rate. The world ratio is 26 induced abortions per 100 known pregnancies.[22]
By gestational age and method
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).[23] 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.[24] 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.[25]
By personal and social factors
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.[26] A 2004 study in which American women at clinics answered a questionnaire yielded similar results.[27] 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.[26] 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.[27] 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.[28]
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.
Health considerations
Early-term surgical abortion is a simple procedure which is safer than childbirth when performed before the 16th week.[29][30] Abortion methods, like most minimally invasive procedures, carry a small potential for serious complications.[31][32] The risk of complications can increase depending on how far pregnancy has progressed.
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.
Some practitioners advocate using minimal anaesthesia so the patient can alert them to possible complications. Others recommend general anaesthesia, to prevent patient movement, which might cause a perforation. General anaesthesia carries its own risks, including death, which is why public health officials recommend against its routine use
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