Induced abortion is the deliberate termination of pregnancy in a manner that ensures that the embryo or fetus will not survive. Societal attitudes toward elective abortion have changed markedly in the past few decades. In some situations the need for abortion is accepted by most people, but political and medical attitudes regarding induced abortion have continued to lag behind changing attitudes. Certain religious objections continue to prevail, resulting in personal, medical, and political conflicts.
Approximately one-third of the world's population lives in nations with nonrestrictive laws governing abortion. Another third live in countries with moderately restrictive abortion laws (ie, in countries where unwanted pregnancies may not be terminated as a matter of right or personal decision but only on broadly interpreted medical, psychologic, and sociologic indications). The remainder live in countries where abortion is illegal without qualification or is allowed only when the woman's life or health would be severely threatened if the pregnancy were allowed to continue.
An estimated 1 of every 4 pregnancies in the world is terminated by induced abortion, making it perhaps the most common method of reproduction limitation. In the United States, estimates of the number of criminal abortions performed before legalization of the procedure ranged from 0.25–1.25 million per year. The number of legal abortions now being performed in the United States approximates 1 abortion per 4 live births. In 1997, there were 1.33 million induced abortions compared with 3.88 million live births.
The procedures being used in the United States for legally induced abortions during the first trimester are relatively safe. Table 58–2 shows that first-trimester legal abortions are consistently safer for the woman than if she used no birth control method and gave birth. Table 58–2 also shows that although the number of maternal deaths related to births steadily increased from 5.6 to 22.6 per 100,000 women as age increased, the age-related increase in number of deaths per 100,000 women per year from legal abortions was insignificant.
In general, the risk of death from legal abortion is lowest when it is performed at 8 menstrual weeks or sooner. During 1988–1997, the overall death rate for women obtaining legally induced abortions was 0.7 per 100,000 legal induced abortions. The risk of death increased exponentially by 38% for each additional week of gestation. Compared with women whose abortions were performed at or before 8 weeks of gestation, women whose abortions were performed in the second trimester were significantly more likely to die of abortion-related causes. The relative risk (unadjusted) of abortion-related mortality was 14.7 at 13–15 weeks of gestation (95% confidence interval [CI] 6.2, 34.7), 29.5 at 16–20 weeks (95% CI 12.9, 67.4), and 76.6 at or after 21 weeks (95% CI 32.5, 180.8). Up to 87% of deaths in women who chose to terminate their pregnancies after 8 weeks of gestation may have been avoidable if these women had accessed abortion services before 8 weeks of gestation.
Legal Aspects of Induced Abortion in the United States
The United States Supreme Court ruled in 1973 that the restrictive abortion laws in the United States were invalid, largely because these laws invaded the individual's right to privacy, and that an abortion could not be denied to a woman in the first 3 months of pregnancy. The Court indicated that after 3 months a state may "regulate the abortion procedure in ways that are reasonably related to maternal health" and that after the fetus reaches the stage of viability (approximately 24 weeks) the states may refuse the right to terminate the pregnancy except when necessary for the preservation of the life or health of the mother. Still, much opposition is raised by various "right-to-life" groups and religious groups. In spite of this opposition, more than 1 million procedures are still performed annually in the United States, with approximately one-third performed on teenaged women. The patient must be informed regarding the nature of the procedure and its risks, including possible infertility or even continuation of pregnancy. The rights of the spouse, parents, or guardian also must be considered and permission obtained when indicated (until the individual woman's rights are clearly established). State laws must be obeyed with special reference to residence, duration of pregnancy, indications for abortion, consent, and consultations required.
Evaluation of Patients Requesting Induced Abortion
Patients give varied reasons for requesting abortion. Because in some cases the request is made at the urging of the woman's parents, in-laws, husband, or peers, every effort should be made to ascertain that the patient herself desires abortion for her own reasons. In addition, one should be certain that the patient knows she is free to choose from among other methods of solving the problem of unplanned pregnancy, such as adoption or single-parent rearing.
Although the majority of abortions are performed as elective procedures (ie, because of social or economic reasons as opposed to medical reasons), some women still request such services for medical or surgical indications. For example, continuation of pregnancy may pose a threat to the life of women with certain medical conditions, such as Eisenmenger's syndrome and cystic fibrosis. Other indications are pregnancy resulting from a rape or pregnancy with a fetus affected with a major disorder, such as trisomy 13. In any event, the ultimate decision rests with the pregnant woman. Help from social agencies should be made available as necessary. A complete social history, medical history, and physical examination are required. Particular attention must be given to uterine size and position; the importance of accurate calculation of the duration of pregnancy (within 2 weeks but preferably within 1 week) cannot be overstated. With uncertainty, pelvic sonography should be used liberally. Routine laboratory tests should include pregnancy tests, urinalysis, hematocrit level, Rh typing, serologic tests for syphilis, culture for gonorrhea, and Pap smear.
Methods of Induced Abortion
Numerous methods are used to induce an abortion: suction or surgical curettage; medical abortion (performed with mifepristone alone, or with a combination of mifepristone and misoprostol or other prostaglandins), induction of labor by means of intraovular or extraovular injection of a hypertonic solution or other oxytocic agent; dilatation and evacuation; extraovular placement of devices such as catheters, bougies, or bags; hysterotomy—abdominal or vaginal; hysterectomy—abdominal or vaginal; and menstrual regulation.
The method of abortion used is determined primarily by the duration of pregnancy, with consideration for the patient's health, the experience of the physician, and the available physical facilities. The risk of repeat abortion is associated with various sociodemographic characteristics, but apparently the method of abortion used is not a risk factor for repeat termination of pregnancy.
Suction curettage on an outpatient basis performed under local or light general anesthesia can be accomplished with a high degree of safety. The safety of outpatient abortion and the shortage of hospital beds have led to the development of single-function, "freestanding" abortion clinics. In addition to providing more efficient counseling and social services, these clinics have effectively reduced the cost of abortion. Many hospitals have "short-stay units," which match the efficiency of outpatient clinics but also offer the backup facilities of the general hospital.
Suction curettage is the safest and most effective method for terminating pregnancies of 12 weeks' duration or less. This technique has gained rapid worldwide acceptance, and more than 90% of induced abortions in the United States are now performed by this method. The procedure involves dilatation of the cervix by instruments or by hydrophilic Laminaria tent (see Induction of Labor by Intra-Amniotic Instillation), followed by insertion of a suction cannula of the appropriate diameter into the uterine cavity (Fig. 58–9). Most procedures are performed using a paracervical block with local anesthesia with or without additional medication for sedation. Standard negative pressures used range from 30–50 mm Hg. Many physicians follow aspiration with light instrumental curettage of the uterine cavity.
Suction method for induced abortion.
The advantages of suction over surgical curettage are that suction curettage empties the uterus more rapidly, minimizes blood loss, and reduces the likelihood of perforation of the uterus. However, failure to recognize perforation of the uterus with a cannula may result in serious damage to other organs. Knowledge of the size and position of the uterus and the volume of the contents is mandatory for safe suction curettage. Moreover, extreme care and slow minimal dilatation of the cervix, with special consideration for the integrity of the internal os, should prevent injury to the cervix or uterus. Attention to the decrease in uterine size that occurs with rapid evacuation helps to avoid uterine injury.
When performed in early pregnancy by properly trained physicians, suction curettage should be associated with a very low failure rate. The complication rate should be <1% for infection, approximately 2% for excessive bleeding, and <1% for uterine perforation. The risk of major complications, such as persistent fever, hemorrhage requiring transfusion, and unintended major surgery, ranges between 0.2 and 0.6% and is proportional to pregnancy duration. The incidence of mortality for suction curettage is approximately 1 in 100,000 patients.
Surgical ("sharp") curettage has been used for first-trimester abortion in the absence of suction curettage equipment. This procedure is performed as a standard dilatation and curettage, such as for the diagnosis of abnormal uterine bleeding or for the removal of endometrial polyps. The blood loss, duration of surgery, and likelihood of damage to the cervix or uterus are greatly increased when surgical curettage is used. In addition, the risk of uterine synechiae or Asherman's syndrome is increased with this approach. Accordingly, suction curettage is generally preferred over sharp curettage for first-trimester termination procedures.
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Medical methods for pregnancy termination in early gestation offer women an alternative to surgical evacuation and have the potential to improve access globally to safe abortion. Several drug regimens are used with varying efficacy, including mifepristone plus misoprostol, misoprostol alone, and methotrexate plus misoprostol. Where available, a mifepristone plus misoprostol regimen is most frequently used and is highly effective for early abortion. Overall, women who choose medical abortion report high levels of satisfaction.
Women with first-trimester pregnancies <49 days from their first day of the last menstrual period may be eligible for medical abortion. An alternative method of medical abortion consists of the administration of an oral antiprogestin (RU-486 [mifepristone]) followed by oral misoprostol 48 hours later. The reported success rate of this method is >90%, provided the protocol is started before 7 weeks from the last menstrual period. Complications include cramping, bleeding due to incomplete abortion, and failure to evacuate the uterus necessitating completion by suction curettage. With one of the more common protocols, 50 mg methotrexate is administered orally, followed by 800 mg misoprostol per vagina (by the patient at home) 3–7 days later using the same tablets as those used for oral dosing. The patient is seen at least 24 hours after the misoprostol administration; a vaginal ultrasound is performed to determine whether there has been passage of the gestational sac. If abortion has not occurred, the misoprostol dose is repeated. The patient is then followed up in 4 weeks; if abortion has not occurred by this time, a suction curettage is typically performed. If fetal cardiac activity is noted on ultrasound, office follow-up is more frequent. Efficacy with this method is up to 98% for pregnancies up to 49 days' gestation; complete abortion rates are inversely proportional to duration of gestation. Nausea is the most frequently reported side effect. Older age, previous spontaneous abortions, and multigravidity are apparently independent risk factors for unsuccessful medical abortion.
Contraindications include active liver disease, active renal disease, severe anemia, acute inflammatory bowel disease and coagulopathy, or anticoagulant therapy.
Induction of Labor by Intra-Amniotic Instillation
The Japanese developed this technique for induced abortion after the first trimester. Currently, the technique is used almost exclusively for initiating midtrimester abortion. The original procedure consisted of amniocentesis, aspiration of as much fluid as possible, and instillation into the amniotic sac of 200 mL hypertonic (20%) sodium chloride solution. In most (80–90%) cases, spontaneous labor and expulsion of the fetus and placenta occur within 48 hours. This technique has been modified, primarily to reduce the injection–abortion interval, and as a result of the development of other agents that initiate labor when instilled intra-amniotically.
Because of the problems associated with hypertonic sodium chloride, many clinicians have used intra-amniotic hyperosmolar (59.7%) urea, usually with oxytocin or prostaglandin or intra-amniotic prostaglandin alone. These approaches result in injection–abortion intervals of 16–17 hours for urea and 19–22 hours for prostaglandin. The urea is instilled in a fashion similar to that described for hypertonic sodium chloride. The prostaglandin, most frequently prostaglandin F2 (PGF2a), usually is instilled as a single dose of 40–50 mg or as 2 doses of 25 mg instilled 6 hours apart. When oxytocin is used to augment these agents, doses as high as 332 mU/min are required to produce uterine contractions because of the relative insensitivity of the myometrium to oxytocin at this stage of pregnancy. To avoid water intoxication, the oxytocin is made up in highly concentrated solutions and given at slow rates.
It is advantageous to soften the unripe cervix with Laminaria tents placed in the cervix a few hours before amniocentesis is performed. Such an approach markedly reduces the risk of cervical injury.
Midtrimester abortion induced by this method must be accomplished with scrupulous aseptic surgical technique, and the patient must be monitored until the fetus and placenta are delivered and postabortion bleeding is under control. The complication rate is high—up to 20% in some institutions—and the mortality rate is comparable to that of term parturition. Fortunately, because first-trimester abortion is now more readily available, more women are consulting their physicians early and thus availing themselves of the much safer suction curettage.
Several types of complications are associated with the use of instillation agents. Retained placenta is the most common problem; rates ranging from 13 to 46% have been reported. The placenta usually can be removed without difficulty using ring forceps and large curettes with the patient under local anesthesia. Hemorrhage may be caused by retained products or atony; coagulopathy is seen in up to 1% of patients in whom hypertonic sodium chloride is used. Infection can occur but is reduced significantly by use of prophylactic antibiotics in high-risk situations (eg, in patients with early ruptured membranes and during injection–abortion intervals >24 hours). Cervical laceration can occur but is reduced by the use of Laminaria tents. Hypernatremia can occur with the use of hypertonic sodium chloride if the drug is absorbed rapidly by the placental bed or if it is given intravascularly by mistake.
Failure of labor to expel the products of conception necessitates either a repetition of the procedure if the membranes are still intact or oxytocin stimulation, usually by intravenous injection or use of the dilatation and evacuation technique.
Emotional stress is an important factor for many women because they are awake at the time of the expulsion of the fetus and the fetus is well formed. (The emotional stress is also a factor for hospital personnel—a problem impossible to avoid.)
Induction of Labor with Vaginal Prostaglandins
Second-trimester abortions are most commonly performed in the United States via dilation and evacuation; however, there are instances in which the use of systemic abortifacients is necessary. Lack of trained staff to perform late abortion procedures, fetal anomalies, and patient preference are important considerations when selecting the method of termination. Second-trimester abortions with misoprostol-only protocols require higher doses, side effects are more common, and the time to complete the abortion is longer in comparison with mifepristone-misoprostol combinations. Feticidal agents are recommended to avoid transient fetal survival. Prostaglandin E2 given intravaginally can be used to induce midtrimester abortion. Vaginal suppositories containing 20 mg are used every 3–4 hours until abortion occurs; the presence or absence of labor determines whether the prostaglandin E2 should be stopped. Misoprostol, a synthetic prostaglandin E1 analogue, is also used. Treatment–abortion intervals, rates of incomplete abortion, and complications are similar to those described for instillation agents. The major disadvantages are significant gastrointestinal side effects, a higher incidence of live abortion, and a more frequent occurrence of fever.
This technique for inducing midtrimester abortion is essentially a modification of suction curettage. Because fetal parts are larger at this stage of pregnancy, most operators use serial placement of Laminaria tents to effect cervical dilatation with less likelihood of injury. Larger suction cannulas and specially designed forceps are used to extract tissue. In most instances, the operation can be performed in the outpatient setting using paracervical block anesthesia and intravenous sedation on patients with pregnancies up to 18 weeks' gestation. Complications include hemorrhage (usually due to atony or laceration), perforation, and rarely infection. Retained tissue is uncommon, especially when tissue is carefully inspected for completion at the end of each procedure. Compared with instillation techniques or vaginal prostaglandin, the overall incidence of complications (in pregnancies up to 18 weeks' gestation) is less with dilatation and evacuation. In addition, most patients prefer the technique because it is an outpatient procedure and the woman does not undergo labor.
Hysterotomy & Hysterectomy
The use of hysterotomy and hysterectomy is currently reserved for special circumstances such as the failure to complete a midtrimester abortion due to cervical stenosis or the management of other complications. Both approaches, compared with other techniques discussed, have unacceptably high rates of morbidity and mortality, and neither should be used as a primary method.
Menstrual regulation consists of aspiration of the endometrium within 14 days after a missed menstrual cycle or within 42 days after the beginning of the last menstrual period by means of a small cannula attached to a source of low-pressure suction, such as a syringe or other suction machine. This is a simple and safe procedure that can be readily performed in the office or outpatient clinic, usually without any anesthetic, although paracervical block can be used if necessary. Menstrual regulation was used extensively in the 1970s and 1980s before reliable, inexpensive, and sensitive urine pregnancy tests became available. It offered a safe early approach to pregnancy termination; however, approximately 40% of women were not pregnant at the time of the procedure. With the advent of urine pregnancy tests that have the ability to document pregnancy even before a missed menstrual period, standard first-trimester suction curettage probably is more widely used. Complications are similar to those described for suction curettage except that persistent pregnancy is more common, particularly when very early menstrual regulation procedures are performed.
RU-486 (mifepristone) is a synthetic drug, developed by French pharmacologists, that acts at least partially as an antiprogestational agent. When given orally in conjunction with a prostaglandin such as misoprostol, it effects first-trimester abortion. Complications include failure to terminate a pregnancy, incomplete abortion, and significant uterine cramping.
Follow-Up of Patients after Induced Abortion
Follow-up care after all procedures must be ensured. After abortion by all methods, human Rho (D) immune globulin (RhoGAM) should be administered promptly if the patient is Rh-negative, unless the male partner is known to be Rh-negative. The patient should take her temperature several times daily and report fever or unusual bleeding at once. She should avoid intercourse or the use of tampons or douches for at least 2 weeks. The physician should discuss with the patient the possibility that emotional depression, similar to that after term pregnancy and delivery, may occur after induced abortion. Follow-up care should include pelvic examination to rule out endometritis and parametritis, salpingitis, failure of involution, or continued uterine growth. Finally, effective contraception should be made available according to the patient's needs and desires.
Long-Term Sequelae of Induced Abortion
Many studies during the past 2 decades have examined the possible long-term sequelae of elective induced abortion. Most of the attention has focused on subsequent reproductive function; unfortunately, many of the studies had inherent biases and serious methodologic flaws. Despite these problems, enough information is available to provide relative estimates of potential risks. Data from some studies suggest that midtrimester pregnancy loss is more common in women who have undergone 2 or more induced or spontaneous abortions. However, women who have undergone 1 procedure have essentially the same risk as women who have experienced a single term pregnancy. Regarding low birthweight, only women who have undergone a first-trimester procedure by sharp curettage under general anesthesia appear to have increased risks. The reason for this association might be related to the method of dilatation used. Finally, studies that have examined both ectopic pregnancy and infertility have failed to show any consistent association between these adverse events and prior induced abortion.
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