abortion, expulsion of the products of conception before the embryo or fetus is viable. Any interruption of human pregnancy prior to the 28th week is known as abortion. The term spontaneous abortion, or miscarriage, is used to signify delivery of a nonviable embryo or fetus due to fetal or maternal factors, as opposed to purposely induced abortion. Therapeutic abortion is an induced abortion performed to preserve the health or life of the mother.

Spontaneous Abortion (Miscarriage)

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.

Induced Abortion

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.

History of Abortion

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.

or spontaneous abortion

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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Common name for mifepristone, a drug used in the first several weeks of pregnancy for inducing abortion. RU-486 blocks the receptors for progesterone, a hormone necessary for the maintenance of pregnancy. The drug causes the breakdown of the uterine lining, which, along with the embryo, is shed through the vagina. It has been available in France for the termination of early pregnancy since 1988 and was approved for use in the U.S. in 2000. The name RU-486 is derived from the manufacturer Roussel-Uclaf and a serial number.

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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 Roe v. Wade decision had the effect of legalizing abortion during the first three months of pregnancy; states were able to implement restrictions on access to abortion after the first trimester, though within constraints set by the courts. Since that decision, there has been a fierce debate between supporters and opponents of a liberalized abortion policy.

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