Abortion
Induced abortion is the intentional ending of a pregnancy by medical means.
Worldwide, the status of abortion varies from being legally banned to being available on request. About two thirds of the women in the world have access to legal abortion. In the United States, laws regarding how late in the pregnancy elective abortion can be performed vary from state to state. In the United States, about 25% of all pregnancies are ended by elective abortion, making it one of the most common surgical procedures performed.
Abortion methods include use of surgery (surgical evacuation) and use of drugs. The method used depends in part on how long a woman has been pregnant. The length of the pregnancy may be hard to estimate if any bleeding has occurred after conception, if the woman is overweight, or if the uterus points backward rather than forward. In these situations, ultrasonography is usually performed to estimate the length of the pregnancy.
Surgical evacuation involves removing the contents of the uterus through the vagina. It is used for about 95% of abortions. Different techniques are used depending on the length of the pregnancy.
A technique called suction curettage is almost always used for pregnancies of less than 12 weeks. Typically, doctors use a small, flexible tube attached to a vacuum source, usually a machine suction pump or hand pump but occasionally a vacuum syringe. The tube is inserted through the opening of the cervix into the interior of the uterus, which is then gently and thoroughly emptied. Sometimes this procedure does not terminate the pregnancy, especially in the first week after the menstrual period is missed.
For pregnancies of 4 to 6 weeks, suction curettage can be performed with little or no dilation of the cervix, because a small suction tube can be used. For pregnancies of 7 to 12 weeks, the cervix is usually dilated because a larger suction tube is used. To reduce the possibility of injuring the cervix, a doctor can use natural substances that absorb fluids, such as dried seaweed stems (laminaria), rather than mechanical devices. Laminaria are inserted into the opening of the cervix and left in place for at least 4 to 5 hours, usually overnight. As the laminaria absorb large amounts of fluid from the body, they expand and stretch the opening of the cervix. Drugs such as prostaglandins can also be used to dilate the cervix.
For pregnancies of more than 12 weeks, a technique called dilation and evacuation is most commonly used. After the cervix is dilated, suction and forceps are used to remove the fetus and placenta. Then the uterus may be gently scraped to make sure everything has been removed. This technique results in fewer minor complications than do the drugs used to induce abortion. However, for pregnancies of more than 18 weeks, dilation and evacuation can cause serious complications, such as damage to the uterus or intestine.
Drugs used to induce abortions include mifepristone (RU-486) and prostaglandins, such as misoprostol. Mifepristone, given by mouth, blocks the action of the hormone progesterone, which prepares the lining of the uterus to support the fetus. Mifepristone is approved only for pregnancies of 7 weeks or less. Prostaglandins are hormonelike substances that stimulate the uterus to contract. They are given by mouth, placed in the vagina, or given by injection. After mifepristone is given, a prostaglandin is given. The regimen now used involves taking 1 to 3 tablets of mifepristone and, 2 days later, taking a prostaglandin (misoprostol) by mouth or vaginally. This regimen causes abortion in about 95% of cases. If abortion does not occur, surgical evacuation is performed.
Complications
In general, abortion has a higher risk of complications than contraception or sterilization, especially for young women. The risk of complications from an abortion is related to the length of the pregnancy and the abortion method used. The longer a woman has been pregnant, the greater the risk. However, complications are uncommon when an abortion is performed by a trained health care practitioner in a hospital or clinic.
The uterus is perforated by a surgical instrument in 1 of 1,000 abortions. Sometimes the intestine or another organ is also injured. Severe bleeding occurs during or immediately after the procedure in 6 of 10,000 abortions. Some techniques can tear the cervix, especially during the 2nd trimester of pregnancy.
Later, infections or blood clots in the legs may develop. Bleeding can occur if part of the placenta is left in the uterus. Very rarely, sterility results from scarring of the uterine lining due to the procedure or a subsequent infection--a disorder called Asherman's syndrome. If the fetus has Rh-positive blood, a woman who has Rh-negative blood may produce Rh antibodies--as in any pregnancy, miscarriage, or delivery. Such antibodies may endanger subsequent pregnancies unless the woman is given injections of Rh0(D) immune globulin (see Section 22, Chapter 258).
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