Induced abortion is the intentional ending of a pregnancy by surgery or drugs.
Worldwide, the status of abortion varies from being legally banned to being available on request. About two thirds of women in the world have access to legal abortion. In the United States, elective abortion (abortion initiated by personal choice) is legal during the 1st trimester (up to 12 weeks). After 12 weeks, whether elective abortion is legal varies from state to state. In the United States, about 50% of pregnancies are unintended, and about 40% of them are ended by elective abortion, making it one of the most common surgical procedures done.
In countries where abortion is legal, abortion is usually safe, and complications are rare. Worldwide, about 13% of deaths in pregnant women are due to abortion. Most of these deaths occur in countries where abortion is illegal.
On the day of the abortion and afterward, women are given antibiotics that are effective against microorganisms that can cause infections in the reproductive tract.
Contraception can be started immediately after an abortion.
Abortion methods include surgery (surgical evacuation) and drugs to stimulate contractions of the uterus. The method used depends in part on how long a woman has been pregnant. Ultrasonography is usually done to estimate the length of the pregnancy. Surgical evacuation can be used for most pregnancies. Drugs can be used for some pregnancies that are very early (less than 9 weeks) or late (more than 15 weeks). For abortions done early in the pregnancy, only a local anesthetic may be needed. For abortions done later, a general anesthetic may be needed.
The contents of the uterus are removed through the vagina. Surgical evacuation is used for more than 95% of abortions in the United States. Different techniques are used depending on the length of the pregnancy.
For pregnancies of less than 12 weeks, suction curettage is almost always used. Typically, doctors use a small, flexible tube attached to a vacuum source, usually a machine suction pump (typically for pregnancies of 9 to 12 weeks) or a hand pump (for pregnancies of less than 9 weeks). Occasionally, a vacuum syringe is used. 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 when the procedure is done during the first week after a menstrual period is missed.
Sometimes doctors have to widen (dilate) the cervix to pass the suction tube through the cervix and into the uterus. For example, for pregnancies of 7 to 12 weeks, the cervix is usually dilated because a larger tube is used. For pregnancies of 4 to 6 weeks, a smaller tube is used, so little or no dilation is usually needed. To reduce the possibility of injuring the cervix during dilation, doctors may 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, dilation and evacuation is usually 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 to induce abortions may be used for pregnancies of less than 9 weeks or more than 15 weeks. Drugs are typically used for very early abortions, before the sac containing the embryo and placenta is clearly visible on an ultrasound scan. These drugs include mifepristone (RU-486) and a prostaglandin, 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.
Prostaglandins are hormonelike substances that stimulate the uterus to contract. They may be used with mifepristone. Prostaglandins may be swallowed, held in the mouth (next to the cheek or under the tongue) until they dissolve, injected, inserted into the rectum, or placed in the vagina. A prostaglandin is given several hours after mifepristone when both are used.
The most common regimen involves taking mifepristone tablets and, several hours to 3 days later, taking a prostaglandin (misoprostol) by mouth or inserting it into the vagina. This regimen causes abortion in about 95 to 98% of women. If abortion does not occur, surgical evacuation is done. For pregnancies of more than 15 weeks, mifepristone tablets can be taken, followed in 1 to 2 days by misoprostol, or misoprostol can be taken alone. For example, two misoprostol tablets placed in the vagina every 6 hours are almost 100% effective within 48 hours.
For pregnancies of more than 9 weeks, women are given the drugs in a hospital and remain in the hospital until the abortion is complete.
After any of these regimens, women must see a doctor to confirm that the pregnancy has been ended.
In general, abortion has a higher risk of complications than contraception or sterilization, especially for young women. However, complications from abortion are uncommon when it is done by a trained health care practitioner in a hospital or clinic. Also, complications occur much less often after an abortion than after delivery of a full-term baby. Serious complications occur in fewer than 1% of women.
The risk of complications is related to the length of the pregnancy: The longer a woman has been pregnant, the greater the risk. Risk is also related to the method used.
Elective abortion does not increase risks for the fetus or woman during subsequent pregnancies.
Most women do not have psychologic problems after an abortion. However, problems are more likely to occur in women who
Last full review/revision August 2013 by Laura Sech; Daniel R. Mishell, Jr., MD; Emily Silverstein