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Abortion

(Interruption of Pregnancy)

By

Frances E. Casey

, MD, MPH, Virginia Commonwealth University Medical Center

Last full review/revision May 2020| Content last modified May 2020
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Induced abortion is the intentional ending of a pregnancy by surgery or drugs.

  • A pregnancy may be ended by surgically removing the contents of the uterus or by taking certain drugs.

  • Complications are uncommon when an abortion is done by a trained health care practitioner in a hospital or clinic.

  • Elective abortion does not increase risks for the fetus or woman during subsequent pregnancies.

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, states can impose restrictions on when abortion can be done. For example, a waiting period or counseling may be required before an abortion can be done. These restrictions vary from state to state.

In the United States, about 50% of pregnancies are unintended, and about 40% of unintended pregnancies 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.

Did You Know...

  • Abortion is one of the most common surgical procedures done in the United States.

Contraception can be started immediately after an abortion done before 28 weeks of pregnancy.

Methods

Abortion methods include

  • Surgical abortion (surgical evacuation): Removal of the contents of the uterus through the cervix

  • Drugs to cause (induce) abortion: Use of drugs to stimulate contractions of the uterus, which expel the contents 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 abortion can be used for most pregnancies up to 24 weeks. Drugs can be used for pregnancies that are less than 11 weeks (often called medical abortion) or that are more than 15 weeks (often called induction).

For abortions done early in the pregnancy, only a local anesthetic may be needed. Conscious sedation (drugs that relieve pain and help women relax but allow women to remain conscious) may also be used. These drugs are usually given by vein. For abortions done later, a stronger sedative is usually required. Rarely, a general anesthetic is needed.

On the day of a surgical abortion, women are given antibiotics that are effective against microorganisms that can cause infections in the reproductive tract.

After any abortion (surgical or medical), women with Rh-negative blood are given injection of Rh antibodies called Rho(D) immune globulin. If the fetus has Rh-positive blood, a woman who has Rh-negative blood may produce antibodies to the Rh factor. These antibodies can destroy the fetus's red blood cells. Treatment with Rho(D) immune globulin reduces the risk that the woman's immune system will make these antibodies and endanger subsequent pregnancies.

Surgical abortion

The contents of the uterus are removed through the vagina. Surgical abortion is used for more than 95% of abortions in the United States. Different techniques are used depending on the length of the pregnancy. They include

Dilation refers to widening the cervix. Different types of dilators may be used, depending on how long the pregnancy has lasted and how many children the woman has had. To reduce the possibility of injuring the cervix during dilation, doctors may use substances that absorb fluids, such as dried seaweed stems (laminaria) or a synthetic dilator. Laminaria are inserted into the opening of the cervix and left in place for at least 4 hours, sometimes overnight. As the dilators absorb large amounts of fluid from the body, they expand and stretch the opening of the cervix. Drugs such as misoprostol (a prostaglandin) can also be used to dilate the cervix.

Typically for pregnancies of less than 14 weeks, dilation and curettage (D and C) with suction is used. For this procedure, a local anesthetic, sometimes with conscious sedation, is used, or rarely, a general anesthetic is used. A speculum is used to spread the walls of the vagina, and the cervix is dilated. Then a flexible tube attached to a vacuum source is inserted into the uterus to remove the fetus and placenta. The vacuum source may be a handheld syringe or similar instrument or an electrical suction machine. Sometimes a small, sharp, scoop-shaped instrument (curet) is inserted to remove any remaining tissue. This procedure is done gently to reduce the risk of scarring and infertility.

For pregnancies between 14 and 24 weeks long, dilation and evacuation (D and E) 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 its contents has been removed. Complications include infection, bleeding, or tears of the cervix or uterus, but complications are rare when surgical abortions are done by trained doctors.

If women wish to prevent future pregnancies, contraception, including a copper intrauterine device (IUD), can be started as soon as the abortion is completed. Then women are less likely to become pregnant unintentionally and to need another abortion.

Medical abortion

Drugs to induce abortions may be used for pregnancies of less than 11 weeks or more than 15 weeks. For an abortion during early pregnancy (less than 10 weeks), a woman can begin taking the drugs at the doctor's office and continue taking the drugs in her home. For an abortion later in pregnancy, the woman has to be admitted to the hospital to take the drugs that will induce labor.

Drugs used include mifepristone (RU 486), followed by a prostaglandin, such as misoprostol.

Mifepristone, given by mouth, blocks the action of the hormone progesterone, which prepares the lining of the uterus for pregnancy. Mifepristone also makes the uterus more sensitive to the second drug that is given (the prostaglandin).

Prostaglandins are hormonelike substances that stimulate the uterus to contract. They may be used with mifepristone. Prostaglandins may be held in the mouth (next to the cheek or under the tongue) until they dissolve, injected, or placed in the vagina.

Medical abortion is a term often used when drugs are used to induce abortions in pregnancies that have lasted less than 11 weeks. The most common regimen involves taking mifepristone tablets in a doctor's office, followed by misoprostol taken 1 to 2 days later. Misoprostol is held next to the cheek until it dissolves, or it is placed in the vagina. The woman may take misoprostol on her own or have a doctor give it to her. This regimen causes abortion in about 92 to 95% of pregnancies that have lasted 8 to 10 weeks. If abortion does not occur, surgical abortion is done.

Induction is a term often used when drugs are used to induce abortions in pregnancies that have lasted more than 15 weeks. Women are given the drugs in a hospital and remain in the hospital until the abortion is complete. Mifepristone tablets can be taken, followed in 1 to 2 days by a prostaglandin, such as 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.

After any of these regimens, women must see a doctor for a follow-up test to confirm that the pregnancy has ended.

Complications

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 who have an abortion. Death after an abortion is very rare. About 6 out of a million women who have an abortion die, compared with about 140 out of a million women who deliver a full-term baby.

The risk of complications is related to the method used.

  • Surgical evacuation: The uterus is perforated by a surgical instrument in 1 of 1,000 abortions. Less often, the intestine or another organ is injured. Severe bleeding occurs during or immediately after the procedure in 6 of 10,000 abortions. The instruments used can tear the cervix, especially in pregnancies of more than 12 weeks. Later, infections may develop. Very rarely, the procedure or a subsequent infection causes scar tissue to form in the lining of the uterus, resulting in sterility. This disorder is called Asherman syndrome.

  • Drugs: Mifepristone and the prostaglandin misoprostol have side effects. The most common are crampy pelvic pain, vaginal bleeding, and gastrointestinal problems such as nausea, vomiting, and diarrhea.

  • Either method: Bleeding and infection can occur if part of the placenta is left in the uterus. If bleeding occurs or if infection is suspected, doctors use ultrasonography to determine whether part of the placenta remains in the uterus.

Later, particularly if the woman is inactive, blood clots may develop in the legs.

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. Giving the woman injections of Rho(D) immune globulin prevents antibodies from developing.

Elective abortion probably 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

  • Had psychologic symptoms before pregnancy

  • Were deeply attached to the fetus

  • Have limited social support or feel stigmatized by their support system

NOTE: This is the Consumer Version. DOCTORS: Click here for the Professional Version
Click here for the Professional Version
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