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Induced Abortion

(Termination of Pregnancy)

by Laura Sech, Penina Segall-Gutierrez, MD, MSc; Emily Silverstein; Daniel R. Mishell, Jr., MD

In the US, abortion of a previable fetus is legal, although state-specific restrictions (eg, mandatory waiting periods, gestational age restrictions) have been recently implemented. In the US, about half of pregnancies are unintended. About 40% of unintended pregnancies are terminated by elective abortion; 90% of procedures are done during the 1st trimester.

In countries where abortion is legal, abortion is usually safe and complications are rare. Worldwide, 13% of maternal deaths are secondary to induced abortion, and the overwhelming majority of these deaths occur in countries where abortion is illegal.

Common methods of inducing abortion are

  • Instrumental evacuation through the vagina

  • Medical induction (stimulation of uterine contractions)

Uterine surgery (hysterotomy or hysterectomy) is a last resort, which is usually avoided because mortality rates are higher. Hysterotomy also results in a uterine scar, which may rupture in subsequent pregnancies.

Pregnancy should be confirmed before abortion is induced. Often, gestational age is established by ultrasonography, but sometimes history and physical examination can accurately confirm gestational age during the 1st trimester. Doppler ultrasonography should be considered if a woman is in the 2nd trimester and has placenta previa or an anterior placenta plus a history of a uterine scar.

Termination of the pregnancy can be confirmed by directly observing removal of uterine contents via ultrasonography used during the procedure. If ultrasonography is not used during the procedure, termination can be confirmed by measuring quantitative serum β–human chorionic gonadotropin (β-hCG) levels before and after the procedure; a decrease of > 50% after 1 wk confirms termination.

Antibiotics effective against reproductive tract organisms (including chlamydiae) should be given to the patient on the day of the abortion. Traditionally, doxycycline is used; 100 mg is given before the procedure and 200 mg is given afterward. After the procedure, Rh 0 (D) immune globulin is given to women with Rh-negative blood.

First-trimester abortions often require only local anesthesia, but trained clinicians may offer sedation in addition. For later abortions, deeper sedation is usually required.

Contraception (all forms) can be started immediately after an induced abortion done at < 28 wk.

Instrumental evacuation

Typically at < 14 wk, dilation and curettage (D & C) is used, usually with a large-diameter suction cannula, inserted into the uterus.

At < 9 wk, manual vacuum aspiration (MVA) can be used. It produces enough pressure to evacuate the uterus. MVA devices are portable, do not require an electrical source, and are quieter than electrical vacuum aspiration (EVA) devices. MVA may also be used to manage spontaneous abortion during early pregnancy. After 9 wk, EVA is used; it involves attaching a cannula to an electrical vacuum source.

At 14 to 24 wk, dilation and evacuation (D & E) is usually used. Forceps are used to dismember and remove the fetus, and a suction cannula is used to aspirate the amniotic fluid, placenta, and fetal debris. D & E requires more skill and requires more training than do other methods of instrumental evacuation.

Often, progressively increasing sizes of tapered dilators are used to dilate the cervix before the procedure. However, depending on gestational age and parity, clinicians may need to use another type of dilator instead of or in addition to tapered dilators to minimize the cervical damage that tapered dilators can cause. Choices include the prostaglandin E 1 analog (misoprostol) and osmotic dilators such as laminaria (dried seaweed stems). Osmotic dilators can be inserted into the cervix and left for ≥ 4 h (often overnight if the pregnancy is >18 wk). Misoprostol dilates the cervix by stimulating prostaglandin release; osmotic dilators dilate the cervix by expanding. Osmotic dilators are usually used at > 16 wk. Misoprostol is usually given buccally 2 to 4 h before the procedure.

If patients wish to avoid pregnancy and the need for subsequent abortions, an intrauterine device (IUD) can be inserted as soon as pregnancy is terminated. This approach makes repeat abortion less likely.

Medical induction

Medical induction can be used for pregnancies of < 9 wk or > 15 wk. If patients have severe anemia, medical induction should be done only in a hospital so that blood transfusion is readily available.

In the US, medical abortion accounts for 25% of abortions done at < 9 wk. For pregnancies of < 9 wk, 2 regimens are effective; both include the progesterone-receptor blocker mifepristone (RU 486) and the prostaglandin E 1 analog misoprostol, as follows:

  • Evidence-based regimen: Mifepristone 200 mg po, followed by misoprostol 800 mcg, self-administered vaginally at 6 to 72 h or buccally at 24 to 48 h (requiring only 2 visits)

  • FDA-approved regimen: Mifepristone 600 mg po, followed by misoprostol 400 mcg po given by a clinician at about 48 h (requiring 3 visits)

The evidence-based regimen is about 98% effective in terminating pregnancies up to 9 wk; the FDA-approved regimen is 95% effective at < 7 wk.

After either regimen, a follow-up visit is required to confirm termination of the pregnancy and, if necessary, to provide contraception.

After 15 wk, pretreatment with mifepristone 200 mg 24 to 48 h before induction reduces induction times. Prostaglandins are used to induce abortion. Options include vaginal prostaglandin E 2 (dinoprostone) suppositories, vaginal and buccal misoprostol tablets, and IM injections of prostaglandin F (dinoprost tromethamine). The typical dose of misoprostol is 600 to 800 mcg vaginally, followed by 400 mcg buccally q 3 h for up to 5 doses. Or, two 200-mcg vaginal tablets of misoprostol q 6 h can be used; abortion occurs within 48 h in almost 100% of cases.

Adverse effects of prostaglandins include nausea, vomiting, diarrhea, hyperthermia, facial flushing, vasovagal symptoms, bronchospasm, and decreased seizure threshold.


Complication rates with abortion (serious complications in < 1%; mortality in < 1 in 100,000) are higher than those with contraception; however, rates are 14 times lower than those after delivery of a full-term infant, and rates have decreased in the last few decades. Complication rates increase as gestational age increases.

Serious early complications include perforation of the uterus (0.1%) or, less often, of the intestine or another organ by an instrument. Major hemorrhage (0.06%) may result from trauma or an atonic uterus. Laceration of the cervix (0.1 to 1%) ranges from superficial tenaculum tears to cervicovaginal tears, rarely with fistulas. General or local anesthesia rarely causes serious complications.

The most common delayed complications include bleeding and significant infection (0.1 to 2%), which usually occur because placental fragments are retained. If bleeding occurs or infection is suspected, pelvic ultrasonography is done; retained placental fragments may be visible on an ultrasound scan. Mild inflammation is expected, but if infection is moderate or severe, peritonitis or sepsis may occur. Sterility may result from synechiae in the endometrial cavity or tubal fibrosis due to infection. Forceful dilation of the cervix in more advanced pregnancies may contribute to incompetent cervix. However, elective abortion probably does not increase risks for the fetus or woman during subsequent pregnancies.

Psychologic complications do not typically occur but may occur in women who

  • Had psychologic symptoms before pregnancy

  • Had significant emotional attachment to the pregnancy (eg, terminated a desired pregnancy for a maternal or fetal medical indication)

  • Have conservative political views about abortion

  • Have limited social support

Key Points

  • About 40% of unintended pregnancies are terminated by elective abortion.

  • Common methods for abortion are instrumental evacuation through the vagina or medical induction (to induce uterine contractions).

  • Before abortion is done, confirm that the woman is pregnant, and if so, determine gestational age based on history and physical examination and/or ultrasonography.

  • For instrumental evacuation, usually use D & C at < 14 wk gestation and D & E at 14 to 24 wk, sometimes preceded by cervical dilation using misoprostol or osmotic dilators (eg, laminaria).

  • For medical induction, give mifepristone, followed by misoprostol at < 9 wk gestation; after 15 wk gestation, pretreat with mifepristone, then give a prostaglandin (eg, dinoprostone vaginally, misoprostol vaginally and buccally, prostaglandin F IM), or misoprostol vaginally.

  • Serious complications (eg, uterine perforation, major bleeding, serious infection) occur in < 1% of abortions.

  • Elective abortion probably does not increase risks in subsequent pregnancies.

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