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. U.S. opponents of abortion have used more militant tactics in recent years 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.

Bibliography

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).

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