Induced Abortion: An Overview for Internists

Key Summary Points Each year, about 2% of all women of reproductive age in the United States have an induced abortion. Most abortions are performed by vacuum aspiration under local anesthesia in freestanding clinics. Use of medical abortion with mifepristone plus misoprostol, methotrexate plus misoprostol, or misoprostol alone is growing in early pregnancy. Abortion remains one of the safest procedures in contemporary practice, with a case-fatality rate less than 1 death per 100000 procedures. Abortion does not lead to an increased risk for breast cancer or other late psychiatric or medical sequelae. The National Abortion Federation and Planned Parenthood Federation of America have helpful Web sites and networks of high-quality clinics. Most internists' practices include large numbers of patients who have had or will seek induced abortion. Although abortion rates are declining, were they to remain stable, an estimated 43% of all U.S. women would have had one or more induced abortions during their reproductive years (1). More than 30 million U.S. women now share this experience. Because surgical abortion is one of the most common operations in contemporary practice and new technologies have emerged over the past decade, this article will provide a primer for internists. We describe the numbers and characteristics of women having abortions, review the methods used, summarize safety data, explain how internists can help patients with referrals to abortion providers if requested, and describe costs. We focus on early induced abortion, which dominates practice in the United States. Our sources were textbooks, review articles, and a search through PubMed using the Medical Subject Heading terms abortion, induced; abortion, legal; and abortion, therapeutic. What Is an Abortion? Abortion is the removal of a fetus or embryo from the uterus before the stage of viability, further defined as 20 weeks' gestation or fetal weight < 500 g (2). The latter descriptors are misleading, however, because fetal viability has not been reported at 20 weeks and weight alone is a poor predictor of viability. The terminology of timing is also confusing. The notion of pregnancy trimesters was adopted by the U.S. Supreme Court in the Roe v. Wade decision of 1973, which legalized abortion nationwide. Regrettably, this obstetrical convention has no basis in biology, and the distinction between first- and second-trimester abortion remains blurred after 3 decades. The practical importance is that states may regulate second-trimester abortions, for example, specifying that abortions must take place in a hospital. However, pregnancy should be considered a continuum, with no clear demarcations once embryogenesis is complete. Two terms describe abortion frequency: the annual rate (number of abortions per women of reproductive age) and ratio (number of abortions per live births). The abortion rate in 1999 was 17 abortions per 1000 women age 15 to 44 years; stated alternatively, about 2% of all women of reproductive age have an abortion each year. The corresponding abortion ratio was 256 abortions per 1000 live births, about 1 induced abortion for every 4 live births (3). Who Has an Abortion? Women who have abortions tend to be young, white, unmarried, and early in pregnancy (Table 1) (3). In 1999, more than half of abortions (58%) were obtained at 8 or fewer weeks of gestation (counted from the first day of the last menstrual period), and 88% were performed before 13 weeks. Suction curettage (also called vacuum aspiration) accounted for nearly all abortions. Several important demographic and medical trends are evident over the past 3 decades (Table 1). The proportion of teenage patients having abortions has declined, as has the proportion of married women. Women have been obtaining abortions at progressively earlier gestational ages and by suction, rather than sharp, curettage (4). As of 1999, over half of all women having abortions were mothers of one or more children. A nationwide survey by the Alan Guttmacher Institute indicated that in 2000 and 2001, most women older than 17 years of age reported a religious affiliation: 43% Protestant, 27% Catholic, 8% other, and 22% no religious affiliation (5). Forty-six percent of women had not used a contraceptive method in the month in which they conceived; inconsistent use of contraceptive method was the main cause of pregnancy among those using contraception (6). Table 1. Characteristics of Women Who Obtained Legal Abortions, United States, 1972 and 1999 How Is a First-Trimester Abortion Provided? When women inquire about abortion, physicians should review all the options for the pregnancy as part of informed consent. These include carrying the pregnancy to delivery and keeping the baby, delivering the baby and giving it up for adoption, or abortion. If abortion is chosen, counseling can then focus on the procedures available; this discussion needs to include the efficacy, benefits, risks, and side effects of surgical abortion and, for women at 9 or fewer weeks of gestation, the alternative of medical abortion. The National Abortion Federation (www.prochoice.org) and Planned Parenthood Federation of America (www.ppfa.org) Web sites provide information about pregnancy options and providers. Physicians need to understand all local and federal regulations related to abortion provision. Abortion can be accomplished by surgical or medical techniques. Surgical abortion entails evacuation of the products of conception through the cervix. The phrase medical abortion refers to early abortion effected by drugs (usually before 9 weeks of gestation) (7). Surgical Abortion Accurate determination of the duration of the pregnancy is an important prerequisite to abortion; as is often the case in surgery, surprises are unwelcome. Therefore, most National Abortion Federation clinics surveyed (66%) use ultrasonography to confirm gestational age before surgical abortion (8). Suction curettage dominates practice in the United States. This technique evacuates the uterine contents with negative pressure; the source of vacuum is commonly an electrical pump or a hand-held syringe. The process involves cervical dilation to a diameter less than 12 mm, followed by evacuation of the uterine contents. Physicians have traditionally inserted a series of progressively larger metal or plastic dilators for dilation. In recent years, use of vaginal or oral misoprostol, a prostaglandin E1 derivative, has grown in popularity. Administration of misoprostol, 400 g (2 tablets) vaginally, for 2 to 3 hours before the abortion softens and opens the cervix (9), although whether this decreases complication rates or improves patient acceptability is unknown. After the cervix is dilated, a plastic cannula is introduced into the uterine cavity and connected to the suction source to perform the abortion. Cannulas range in diameter from 4 to 14 mm. Suction curettage is safer, faster, and more comfortable than its predecessor, sharp curettage (also termed D & C for dilation and curettage). Procedure time is usually less than 5 minutes. Local anesthesia is the most common approach to pain control. In a recent survey of providers, 58% used paracervical block with or without oral premedication, 32% combined paracervical block with intravenous sedation, and 10% used general anesthesia (8). Local anesthesia is both safer and less expensive than general anesthesia, although pain relief is not complete. With local anesthesia, most women have discomfort similar to bad menstrual cramps during the operation; this resolves soon after the operation is finished. Most women are comfortable at the time of discharge. After the abortion, the woman is monitored in a recovery room for about 30 minutes. Before discharge, she receives information about warning signs of common complications, and most women leave the clinic with their chosen method of contraception. Standard practice is for the physician or a designee to inspect the aspirated tissue to confirm successful completion of the abortion and to exclude an unsuspected ectopic pregnancy. Formal pathologic examination of the products of conception is unnecessary (10). Women who are Rh negative receive Rh immunoglobulin. Many women resume their usual activities the same day as the abortion, although some prefer to wait another day before returning to routine daily activity. A follow-up visit is usually scheduled in 2 or 3 weeks, but evidence supporting the benefit of this visit is lacking. Moreover, only about half of women opt to return. The principal use of the follow-up visit may be management of contraception. If an internist sees an asymptomatic woman for follow-up after abortion, a pelvic examination is typically performed but is unnecessary. Likewise, no laboratory tests are indicated. Most important, the patient should be asked how she is doing with her chosen contraceptive. Medical Abortion The most commonly used medical abortion regimen throughout the world is mifepristone followed by a prostaglandin analogue, usually misoprostol. However, in areas without access to mifepristone, methotrexate and misoprostol or misoprostol alone are acceptable alternatives. Mifepristone regimens result in higher rates of complete abortion and cause expulsion more rapidly than those using methotrexate and misoprostol and misoprostol alone (11, 12). Mifepristone, a derivative of the progestin norethindrone, binds strongly to the progesterone receptor without activation, thereby acting as an antiprogestin. Mifepristone results in separation of the trophoblast from the endometrial wall; it also increases endogenous prostaglandin release and sensitizes the myometrium to exogenous prostaglandins. In addition, mifepristone softens the cervix to allow expulsion. Initial studies of mifepristone attempted to find the optimal regimen to achieve acceptable rates of expulsion. However, not until investigators began following mifepristone wi