Abortion

In medicine, an abortion is the premature exit of the products of conception (the fetus, fetal membranes, and placenta) from the uterus. It is the loss of a pregnancy and does not refer to why that pregnancy was lost. A spontaneous abortion is the same as a miscarriage. The miscarriage of 3 or more consecutive pregnancies is termed habitual abortion.

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1. Expulsion from the uterus of an embryo or fetus prior to the stage of viability (20 weeks' gestation or fetal weight <500 g). A distinction made between a. and premature birth : premature infants are those born after the stage of viability but prior to 37 weeks. A. may be either spontaneous (occurring from natural causes) or induced (artificial or therapeutic). 2. The arrest of any action or process before its normal completion.

- ampullar a. a. resulting from pregnancy in the ampulla of the fallopian tube.

- complete a. 1. the complete expulsion or extraction from its mother of a fetus or embryo; 2. complete expulsion of any other product of gestation. ( e.g., blighted ovum).

- criminal a. termination of pregnancy in violation of law. SYN: illegal a..

- elective a. an a. without medical justification but done in a legal way, as in the United States.

- habitual a. SYN: recurrent a..

- illegal a. SYN: criminal a..

- incomplete a. a. in which part of the products of conception have been passed but part (usually the placenta) remains in the uterus.

- induced a. a. brought on purposely by drugs or mechanical means.

- inevitable a. a. characterized by rupture of the membranes or the cervical dilation in a previable pregnancy in the presence of vaginal bleeding and uterine contractions.

- infected a. a septic complication of an a..

- menstrual extraction a. a technique for aspiration of early products of conception from the uterus a few days after the first missed menstrual period.

- missed a. a. in which the fetus dies in utero but the product of conception is retained in utero for two months or longer.

- recurrent a. the loss of 3 or more sequential pregnancies before 20 weeks of gestation. SYN: habitual a..

- septic a. an infectious a. complicated by fever, endometritis, and parametritis.

- spontaneous a. a. that has not been artificially induced. SYN: miscarriage.

- therapeutic a. a. induced because of the mother's physical or mental health, or to prevent birth of a deformed child or a child resulting from rape.

- threatened a. cramplike pains and slight show of blood that may or may not be followed by the expulsion of the fetus during the first 20 weeks of pregnancy.

- tubal a. rupture of an oviduct, the seat of ectopic pregnancy, or extrusion of the product of conception through the fimbriated end of the oviduct; aborted ectopic pregnancy, the pregnancy having originated in a fallopian tube. SYN: aborted ectopic pregnancy.

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abor·tion ə-'bȯr-shən n

1) the termination of a pregnancy after, accompanied by, resulting in, or closely followed by the death of the embryo or fetus:

a) spontaneous expulsion of a human fetus during the first 12 weeks of gestation compare MISCARRIAGE

b) induced expulsion of a human fetus

c) expulsion of a fetus of a domestic animal often due to infection at any time before completion of pregnancy see CONTAGIOUS ABORTION, TRICHOMONIASIS (b), VIBRIONIC ABORTION

2) arrest of development of an organ so that it remains imperfect or is absorbed

3) the arrest of a disease in its earliest stage <\abortion of a cold>

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n.

the expulsion or removal of an embryo or fetus from the uterus at a stage of pregnancy when it is incapable of independent survival (i.e. at any time between conception and the 24th week of pregnancy). In threatened abortion there may be abdominal pain and bleeding from the uterus but the fetus is still alive; once the fetus is dead abortion becomes inevitable. Abortion is incomplete so long as the uterus still contains some of the fetus or its membranes. Abortion may be spontaneous or it may be induced for medical or social reasons (termination of pregnancy). Habitual (or recurrent) abortion is the occurrence of three consecutive pregnancy losses before 20 weeks' gestation, with fetuses weighing under 500 grams. The presence of a uterine abnormality, such as bicornuate uterus or cervical incompetence, may account for 10-15% of recurrent abortions.

Procuring or attempting to procure abortion are both criminal offences in the UK unless carried out within the terms of the Abortion Act 1967 and the subsequent Abortion Regulations 1991. Two doctors must agree that termination of pregnancy is necessary for one of the reasons specified in the Regulations, and the procedure must be carried out in an approved hospital or clinic. Methods in current use include the administration of drugs, e.g. mifepristone with or without the addition of prostaglandins (e.g. gemeprost). The surgical methods of termination of pregnancy include vacuum aspiration of the products of conception through an intrauterine cannula, dilatation and curettage, and uterine evacuation by ovum forceps. Termination carries little risk early in pregnancy, but complications are more likely to occur after the 13th week of pregnancy.

Nonmedical people make a distinction between abortion and miscarriage, the former being a procedure deliberately carried out to end the pregnancy, the latter being an accidental occurrence. The medical profession increasingly recognizes this useful distinction.

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abor·tion (ə-borґshən) [L. abortio] 1. premature expulsion from the uterus of the products of conception, either the embryo or a nonviable fetus. 2. premature stoppage of a natural or a pathological process.