Abortion, in its most commonly used sense, refers to the deliberate early termination of pregnancy, resulting in the termination of the embryo or fetus. Medically, the term also refers to the early termination of a pregnancy by natural causes ("spontaneous abortion" or miscarriage, which ends 1 in 5 of all pregnancies, usually within the first 13 weeks) or to the cessation of normal growth of a body part or organ. What follows is a discussion of the issues related to deliberate or "induced" abortion.
(Note: "morning after or "emergency" contraceptive drugs that are taken within 72 hours of sex interfere with the release of eggs from the ovary or with fertilization, and so are not generally considered to be forms of abortion unless they interfere with implantation of a zygote when taken later).
Depending on the stage of pregnancy an abortion is performed by a number of different methods. For the earliest terminations (before nine weeks or so) a chemical abortion is the usual method. The procedure consists of giving either methotrexate or mifepristone (RU-486) followed by administration of misoprostol. Approximately 8% of these abortions require surgical followup.
Concurrent with chemical abortion and extending up until around the fifteenth week suction-aspiration or vacuum abortion is the most common approach. replacing the more risky dilation and curettage (D & C). Manual vacuum aspiration (MVE) consists of emptying the uterus by suction using a manual syringe. From the fifteenth week up until around the eighteenth week a surgical 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 suction curettage consists of emptying the uterus by suction using a special apparatus. Curettage is cleaning the walls of uterus with a curette. Dilation and curettage (D&C) is a standard gynaecological procedure performed for a variety of reasons.
As the fetus size increases other techniques must be used to secure abortion in the third trimester, premature expulsion of the fetus can be induced with prostaglandin, this can be coupled with injecting the amniotic fluid with saline or urea solution. Very late abortions can be brought about by the controversial intact dilation and extraction (D & X) or a hysterotomy abortion, similar to a caesarian section, and requiring the surgical decompression of the fetus's head before evacuation. This is also referred to as Intact dilation and extraction.
See also: Sex selective abortion, herbal contraception, partial-birth abortionMethods of performing abortion