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Abortion

(Interruption of Pregnancy)

By

Frances E. Casey

, MD, MPH, Virginia Commonwealth University Medical Center

Last full review/revision Feb 2022| Content last modified Sep 2022
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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.

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

In the United States, about 50% of pregnancies are unintended. About 40% of unintended pregnancies are ended by induced abortion, making it one of the most common surgical procedures done. About 90% of abortions are done during the 1st trimester. States may set restrictions (such as mandatory waiting periods, age of the fetus, or notarized consent for minors). These restrictions may delay or prevent access to abortion.

In countries where abortion is legal, 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 highly restricted or illegal.

Pregnancy is confirmed before an abortion is started. Often, ultrasonography is used to determine the age of the fetus, but sometimes a health care practitioner's evaluation can determine the age during the 1st trimester. If women have risk factors for problems related to an abortion (such as heart or lung disease, seizures, or a history of cesarean deliveries), they may require further evaluation.

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 of Abortion

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 medication 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. Rarely, a general anesthetic is needed.

Before a surgical abortion, women are given antibiotics that are effective against infections in the reproductive tract.

After any abortion (surgical or medication), 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 Rh Incompatibility . 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. Treatment with immune globulin may be optional before 8 weeks of pregnancy.

Surgical abortion

The contents of the uterus are removed through the vagina. 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 Medication abortion ) 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. A speculum is used in the vagina to enable the practitioner to see the cervix. A local anesthetic (such as lidocaine) is injected into the cervix to reduce discomfort, 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. A sharp curet may be used gently to make sure all products of conception have been removed.

Medication 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 11 weeks), the abortion process can be completed at home. For an abortion later in pregnancy, the woman typically is admitted to the hospital to take the drugs that will induce labor.

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

Mifepristone, taken 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).

Practitioners confirm the completion of the abortion by one of the following:

  • Ultrasonography

  • A urine test to measure human chorionic gonadotropin (hCG) on the day the drug is given and 1 week later (hCG is produced early in pregnancy)

  • After a medication abortion, a urine pregnancy test 5 weeks

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 or placed in the vagina.

For abortions in pregnancies that have lasted less than 11 weeks, the most common regimen involves taking mifepristone tablet, 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 mifepristone and misoprostol on her own or have a doctor give it to her. This regimen causes abortion in about

  • 95% of pregnancies that have lasted 8 to 9 weeks

  • 87 to 92% of pregnancies that have lasted 9 to 11 weeks

An additional dose of misoprostol improves effectiveness in pregnancies that have lasted longer than 9 weeks.

If a medication abortion is unsuccessful, a surgical abortion may be required.

Induction is a term often used when drugs are used to induce abortions in pregnancies that have lasted more than 15 weeks. Women remain in the clinic or 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.

Complications of Abortion

Complications from abortion are rare 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 older the fetus is, the higher the number of complications.

The risk of complications is related to the method used.

  • Surgical evacuation: Complications are rare when surgical abortions are done by trained practitioners. The uterus is torn (perforated) by a surgical instrument in fewer than 1 of 1,000 abortions. Injury of the intestine or another organ is even rarer. Severe bleeding during or immediately after the procedure occurs in 6 of 10,000 abortions. 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, practitioners 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 Prevention Rh incompatibility occurs when a pregnant woman has Rh-negative blood and the fetus has Rh-positive blood. Rh incompatibility can result in destruction of the fetus’s red blood cells, sometimes... read more prevents antibodies from developing. Immune globulin may be optional for pregnancies lasting less than 8 weeks.

Psychologic problems after an abortion are more likely if the following are present

  • Psychologic symptoms before pregnancy

  • Limited social support or a sense of disapproval in their support system

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