Induced Abortion Throughout history, women have used abortion to terminate unwanted pregnancies. Legal abortion is available to about 2/3 of the women in the world; about 1/12 of all women live in countries where abortion prohibitions are strictly enforced. In the USA, abortion is permitted on request in the 1st trimester; after that, abortion is regulated by each state.
In the USA, the number of reported abortions has remained relatively stable during the past decade; about 1.5 to 1.6 million abortions per year are performed. In 1994, there were about 6 million pregnancies in the USA; about 25% were terminated by abortion. About 25% of women who have abortions are < 20 yr, 35% are 20 to 24 yr, and 40% are >= 25 yr. About 90% of abortions are performed in the 1st trimester (<= 12 wk), with > 50% of these at <= 8 wk.
Abortion methods currently used are instrumental evacuation through the vagina; medical induction, with stimulation of uterine contractions; and uterine surgery (hysterotomy or hysterectomy). The procedure chosen varies with the length of gestation. A local anesthetic is usually preferred in 1st-trimester abortions; a general anesthetic may be needed for late abortions.
Instrumental evacuation is used in 97% of abortions. In pregnancies of < 12 wk, curettage is virtually the only procedure used. Suction curettage at 4 to 6 wk requires little or no dilation of the cervix. The cannula, attached to a vacuum source, is inserted through the cervix. The uterine cavity is gently and thoroughly curetted. Failure to terminate the pregnancy occurs more frequently in these early weeks than later.
After 7 wk of gestation, dilation and curettage (D & C) is usually performed; the cervix usually requires dilation to accommodate the larger-diameter suction cannulas needed to evacuate the larger amount of products of conception. The cervix may be gently dilated using tapered dilators in progressively increasing sizes until the diameter of the desired cannula is reached. The size of the cannula generally correlates with gestational age. Laminaria (dried seaweed stems) or other osmotic dilators are frequently used because they help reduce potential injury to the cervix by mechanical dilation. They are inserted into the cervical canal through the internal os and left in place for at least 4 h, usually overnight; expansion of the laminaria and/or stimulation of prostaglandin release dilates the cervix.
In pregnancies of > 12 wk, dilation and evacuation (D & E) is the method most commonly used. In this procedure, the cervix is dilated (usually with multiple laminaria or other osmotic dilators). Forceps are used to dismember and remove the fetus, and a 14- to 16-mm (about 1.5 cm) suction cannula is used to aspirate the amniotic fluid, placenta, and fetal debris. In more advanced pregnancies, multiple laminaria may be used to gently dilate the cervix to 3 to 4 cm to make the evacuation easier and safer. D & E requires more skill than does suction curettage.
Although D & E has lower rates of minor morbidity than medical induction through 20 wk, medical induction is still used--especially after 18 wk--because after that time, D & E has a greater risk of major morbidity (including bowel injury and uterine injury requiring hysterectomy).
Abortion may be initiated by medical induction of uterine contractions, especially in the 2nd trimester. In the USA, instillation of a hypertonic saline solution is no longer used because of maternal complications, such as hypernatremia, coagulopathy, hemorrhage, infection, and cervical injuries.
Prostaglandins stimulate uterine contractions. Either vaginal prostaglandin E2 (dinoprostone) suppositories, placement of vaginal prostaglandin E1 analog (misoprostol) tablets, or IM injections of prostaglandin F2I (dinoprost tromethamine) can be used. Intravaginal placement of two 100-µg tablets of misoprostol q 12 h is as successful as prostaglandin E2 but has fewer adverse effects and costs less. The success rate after 48 h of treatment is nearly 90%. These techniques are likely to result in abortion of a live fetus. Using IV oxytocin accelerates the process but increases the risk of lower uterine tears. In the 2nd trimester, using laminaria or other osmotic dilators singly or multiply before medical induction usually shortens labor and decreases the incidence of cervicovaginal lacerations.
Adverse effects of prostaglandins include nausea, vomiting, diarrhea, hyperthermia, facial flushing, vasovagal symptoms, and bronchospasm. Prostaglandins may precipitate bronchial asthma in susceptible women; in women with severe kidney or liver disease, activation of the drug may be decreased. Women with epilepsy may develop seizures.
Mifepristone, a progesterone-receptor blocker, is very effective in terminating pregnancy of < 7 wk when it is combined with a prostaglandin. Currently, this drug is available only in a few European countries and in China.
Hysterotomy--in essence a cesarean section--is rarely indicated. The uterine scar increases the risk of uterine rupture in subsequent pregnancies. Hysterectomy should be reserved for women who have had an indication for this procedure and who recognize that permanent sterilization follows. The mortality of these procedures is 44 times that of a 1st-trimester curettage.
Complications
In general, contraception has a much lower complication rate than abortion, especially for young women. For abortion, the rate of serious complications is < 1% and the mortality rate is < 1 in 100,000 cases.
Complication rates are directly related to the gestational age and to the method used. They increase as gestational age increases. An ultrasound examination should be performed if any doubt exists about the gestational age; eg, bleeding after conception may be misconstrued as the last menstrual period, and a retroflexed uterus or the uterus of an obese patient may be difficult to assess. Serious early complications include perforation of the uterus (0.1%) by one of the instruments used for abortion; sometimes the intestine or other organs are also injured. Major hemorrhage (0.06%) may occur secondary to trauma or an atonic uterus. Laceration of the cervix (0.1 to 1%) ranges from superficial tenaculum tears to cervicovaginal fistula (associated with an instillation procedure in the 2nd trimester). Untoward effects may result from general or local anesthetics.
The most common delayed complications include postabortion bleeding due to retention of placental fragments; thrombophlebitis; and infection (0.1 to 2%), ranging from mild endometritis to severe pelvic inflammation, peritonitis, and septicemia. Sterility may occur secondary to pelvic infection or to synechiae in the endometrial cavity. Rh sensitization may occur in susceptible women who have Rh-negative blood if Rh immune globulin is not used (see Blood Products in Ch. 129 and Erythroblastosis Fetalis in Ch. 252). The effect of elective abortion on subsequent pregnancies continues to be disputed. Recent extensive studies report no significantly increased risk. Forceful dilation of the cervix in more advanced pregnancies may predispose to incompetent cervix. Complication rates, including mortality, have progressively decreased, especially since 1972. Performing suction curettage in the 1st trimester is safer than terminating a pregnancy by D & E, prostaglandins, or hysterotomy in the 2nd trimester.
Psychologic Aspects
For most women, abortion is not a threat to mental well-being and has no adverse psychologic sequelae. Before abortion was easily and legally obtainable, psychologic difficulties may have been related more to the problems and stress desperate women encountered in obtaining the procedure. The women more prone to psychologic sequelae are those who had psychiatric symptoms before pregnancy, who terminated a desired pregnancy for medical reasons (maternal or fetal), who have considerable ambivalence, who are young adolescents, or who had a late abortion.
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