Complications of Medical Abortion

This page contains the following sections:

"Incomplete Abortion"
Failed Abortion
Infection
Ectopic Pregnancy
Death

Serious complications are uncommon following both medical and surgical abortion. Complications associated with surgical abortion, such as uterine perforation and adverse reactions to anesthesia, result either directly or indirectly from the need to instrument the uterus. Successful medical abortion avoids these types of complications, as it terminates pregnancy without the need for invasive surgery and anesthesia.

The main complications associated with medical abortion are persistent nonviable gestational sac, persistent bleeding requiring surgical intervention (described collectively as "incomplete abortion" in some medical abortion studies), continuing pregnancy, hemorrhage (discussed in Case Presentation 2), infection, and undiagnosed ectopic pregnancy.
 

 
 

After reading this section, you should be able to answer the following question:

In clinical trials, which findings have NOT been included in the definition of an "incomplete abortion"?

"Incomplete Abortion"
In most early medical abortion research trials involving mifepristone/misoprostol, the outcome of "incomplete abortion" included women with a persistent nonviable gestational sac on ultrasonography 2 weeks after administration of mifepristone. Some trials also included cases of prolonged bleeding resulting in suction curettage, a clinical presentation suggestive of failure to expel all pregnancy tissue.

Early protocols mandated surgical evacuation of the uterus when the sonogram at the 2-week follow-up visit revealed a nonviable pregnancy.3,6,19,20,27,30 However, research trials using methotrexate/misoprostol indicate that expulsion of the gestational sac will generally occur eventually - an average of 22 to 29 days after methotrexate administration.10,11,26,31,32

In light of these findings, the most recent U.S. mifepristone studies extended the allowable observation period for a persistent sac to approximately 36 days.4,7,8

A meta-analysis of medical abortion trials by Kahn and colleagues5 reported incomplete abortion rates of 2.9% for mifepristone/misoprostol regimens and 2.4% for methotrexate/misoprostol regimens in women with pregnancies of ≤ 49 days' gestation. For both mifepristone and methotrexate regimens, incomplete abortion rates increased with advancing gestational age. With mifepristone regimens, the use of oral misoprostol resulted in higher rates of incomplete abortion than the use of vaginal misoprostol (6.4% vs. 2.1%, p = .05).

All women should undergo follow-up within 2 weeks after initiation of the medical abortion regimen to confirm whether or not the abortion is complete. Symptoms of persistent or heavy bleeding raise the possibility of incomplete abortion. However, some women with a retained gestational sac will be asymptomatic.

If the history reveals either no bleeding or continued, heavy bleeding, or examination reveals an enlarged uterus, an ultrasound examination is warranted to rule out incomplete abortion or continuing pregnancy. If the patient has a persistent nonviable pregnancy, the ultrasound typically shows a gestational sac without signs of continued development or embryonic cardiac activity.

Management of a persistent gestational sac depends on several factors, including the patient's medical condition and preferences, the provider's experience and judgment, and logistical factors affecting follow-up (e.g., the patient's need for child care and transportation). Click here to view Figure 4.

Patients who are clinically stable have several options: observation and re-evaluation, repeat misoprostol, or uterine aspiration. Women who opt for simple observation can wait an additional 3 to 4 weeks for the sac to pass. Some patients are reassured to know they will no longer have pregnancy-related symptoms during this waiting period.

 
Click here to read Case Presentation 5.

In most cases, a repeat ultrasound at the follow-up visit will confirm expulsion of the gestational sac. When expulsion has not yet occurred, some providers will use an additional dose of misoprostol. In a recent study, more than half of the women treated with a second dose of misoprostol at the one-week followup visit  subsequently expelled the sac.67 Incomplete abortion associated with excessive bleeding or infection is an indication for suction curettage.

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After reading this section, you should be able to answer the following question:

Results of clinical trials using the FDA-approved regimen of mifepristone and oral misoprostol demonstrate what relationship between gestational age and rates of continuing pregnancy?

Failed Abortion
"Continuing pregnancy" occurs when the medical abortion regimen fails to terminate the pregnancy. The diagnosis is established when ultrasound reveals a viable pregnancy with embryonic cardiac activity 2 weeks after initiating treatment.

Continuing pregnancy is uncommon in women undergoing medical abortion at ≤ 49 days' gestation. The study by Spitz and colleagues3 using the FDA-approved medical abortion regimen reported rates of continuing pregnancy of 1% for gestations ≤ 49 days, 4% for gestations between 50 and 56 days, and 9% for gestations between 57 and 63 days.

A meta-analysis of medical abortion trials published by Kahn and colleagues5 in 2000 reported comparable continuing pregnancy rates for regimens using mifepristone and misoprostol or methotrexate and misoprostol in women with gestations ≤ 49 days.

In a randomized trial comparing mifepristone followed by oral or vaginal misoprostol in women with pregnancies of ≤ 63 days, El-Refaey and colleagues27 found a significantly higher rate of ongoing pregnancy with the oral regimen (7% vs. 1%, p = .01). This finding is supported by U.S. trials showing continuing pregnancy rates of < 1% in women using mifepristone and vaginal misoprostol up to 63 days' gestation.7 Rates of continuing pregnancy following mifepristone and buccal misoprostol are similarly low.63

When continuing pregnancy occurs, women are likely to report little to no bleeding after taking abortifacients, although this outcome is not universal. Commonly, pregnancy symptoms are still present if they were present prior to abortion. Physical examination may not be diagnostic, depending on the initial gestational age and the time interval to follow-up, as well as the position of the uterus, the patient's body habitus and the experience of the examiner. An ultrasound finding of an embryo with cardiac activity at the 2-week follow-up visit establishes the diagnosis. If the gestation is less than 47 days (embryonic pole less than 5 mm), it may be too early to detect cardiac activity sonographically. (A more detailed discussion of sonographic interpretation and gestational dating can be found in the module titled "The Role of Ultrasound, hCG Assays, and Clinical Assessment in Medical Abortion.")

 
Click here to read Case Presentation 6.

In this instance, ongoing pregnancy would still be the correct diagnosis if the post-treatment sonogram shows continued development of the gestational sac or embryo consistent with the elapsed time since the initial visit. When the follow-up evaluation reveals a continuing pregnancy, surgical aspiration is indicated to complete the abortion.2

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After reading this section, you should be able to answer the following question:

What may indicate the presence of infection?

Infection
Endometritis is a rare complication of medical abortion, which typically involves no instrumentation of the cervix or uterine cavity. In large trials including 1000 participants or more, infection rates have varied from 0.1% to 0.9%.49-55

Whereas some authors recommend the universal use of peri-operative antibiotics for surgical abortion,57 there is currently insufficient evidence to support such treatment with medical abortion. A large retrospective multisite analysis of abortions offered by one national organization58 reported that the rate of serious infection after medical abortion declined after a change from vaginal to buccal administration of misoprostol and again after a change to routine provision of antibiotics, with an absolute risk reduction of 0.67/1,000 and 0.19/1,000, respectively. However,  as the risk of serious infection was  initially extremely low, a randomized controlled trial was not feasible, and based on this level of evidence and considering the lack of information about any adverse effects of antibiotic use,  a universal change in regimen is not definitively supported. Rare fatal infections with Clostridium sordellii and perfringens have been reported in North America in women who received mifepristone and misoprostol.59, 60 Symptoms seen with such infections include weakness, nausea, vomiting or diarrhea with or without abdominal pain that persists after expulsion of the pregnancy. Although patients typically lack a fever, they exhibit rapid pulse, low blood pressure, and very high red and white blood cell counts. The U.S. Centers for Disease Control and Prevention have also reported deaths from the same organism after other reproductive outcomes, including in two women who had spontaneous abortions without use of mifepristone or misoprostol.61 On the basis of available information, serious infection and death from medical abortion seem most likely related to the physiologic process of abortion, whether spontaneous or induced, and not the medicines themselves.

Severe neutropenia has been described in two women who received methotrexate 50 mg/m2 intramuscularly for the treatment of ectopic pregnancy56. A sustained fever exceeding 38°C following the use of methotrexate, especially if stomatitis is also present, requires a complete blood count for evaluation of neutropenia. In the very rare event of severe neutropenia following the use of methotrexate, the theoretical risk of secondary opportunistic infection warrants appropriate preventive measures.

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After reading this section, you should be able to answer the following question:

When should ectopic pregnancy be suspected?

Ectopic Pregnancy
Ectopic pregnancy is a complication of pregnancy itself rather than a complication resulting from medical abortion treatment. For reasons that remain obscure, the rate of ectopic pregnancy in women presenting for early abortion is much lower than the rate of 1.9% for all pregnancies in the United States.

Of the approximately 3,000 patients involved in trials by the Spitz group3 and the Peyron group,14 only one case of ectopic pregnancy was reported. The incidence of ectopic pregnancy among patients seeking early surgical abortion at < 6 weeks' gestation is 6.7 per 1,000.9

Given that patients seeking medical abortion present to their providers early in pregnancy, the critical time for diagnosis of ectopic gestation, providers must remain vigilant to detect this complication, and have clear, established protocols for diagnosis and management.

At the initial visit, women with ectopic pregnancy may be asymptomatic or report a history of lower abdominal pain or intermittent bleeding. The pelvic examination may be normal or reveal an adnexal mass. Standard diagnostic evaluation includes pelvic ultrasound examination and quantitative -hCG measurements.

In normal pregnancy, experienced sonographers using a transvaginal probe should see a gestational sac within the uterus by the time the -hCG level reaches approximately 2,000 mIU/mL. Failure to do so indicates ectopic pregnancy until proven otherwise. The presence of a gestational sac with a yolk sac or embryonic cardiac activity within the fallopian tube establishes the diagnosis, but these findings are not invariably present.

Salpingectomy remains the most commonly performed surgical procedure for treatment of ectopic pregnancy in the United States.35 Over the past 20 years, however, surgical procedures to preserve the oviduct have been developed. In many cases of early unruptured ectopic pregnancy, medical management is another therapeutic option.36

Methotrexate, although it is not FDA-approved for this indication, is the only abortifacient that has proven useful in treating ectopic pregnancy,37 although it is not 100% effective and is an alternative to surgery only under certain specific circumstances.38 Mifepristone is ineffective in treating tubal pregnancy, possibly because the fallopian tubes lack progesterone receptors.39 Misoprostol is not effective for the treatment of ectopic pregnancy.

The 50 mg/m2 dose of intramuscular methotrexate used in early medical abortion regimens is the same as that used in single-dose methotrexate protocols for treatment of early unruptured ectopic pregnancy. In a recent study of 350 women treated with methotrexate for ectopic pregnancy, success rates correlated inversely with pretreatment serum -hCG levels and the presence of embryonic cardiac activity.40

 
Click here to read Case Presentation 8.

Success rates decreased from 98% at -hCG concentrations < 1,000 mIU/mL to 93% at concentrations of 1,000 - 1,999 mIU/mL and to 92% at levels of 2,000 - 4,999 mIU/mL. Close clinical and -hCG monitoring is essential after methotrexate administration, because tubal rupture can occur even with declining serum concentrations of -hCG.38 A detailed discussion of the management of suspected or diagnosed ectopic pregnancy is beyond the scope of this document.

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Death

Reports of death after medical abortion are very rare - less than 1 in 100,000 cases, a rate comparable to that for early surgical abortion and for miscarriage.41

Since the year 2000, more than 1.1 million women in the United States have undergone mifepristone-induced abortion. Six women in North America have died as a result of toxic shock secondary to a rare bacterial infection of the uterus following medical abortion with mifepristone and misoprostol. This type of fatal infection has also been observed to occur following miscarriage, childbirth and surgical abortion, as well as other contexts unrelated to pregnancy.42,43 The Centers for Disease Control and Prevention's continuing investigations have found no causal link between the medications and these incidents of infection.43,44

Although the Food and Drug Administration (FDA) has issued an updated advisory for warning signs of infection following medical abortion in April of 2006, it has recommended that there be no changes in the current standards for provision of medical abortion.44,45  The FDA does not have sufficient information to recommend the use of prophylactic antibiotics. Reports of fatal sepsis in women undergoing medical abortion are very rare. Prophylactic antibiotic use carries its own risk of serious adverse events such as severe or fatal allergic reactions, and may also contribute to the development of multi-drug resistant bacteria. Finally, it is not known which antibiotic and regimen (what dose and for how long) would be effective in preventing these rare fulminant infections.43,46

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Proceed to Vacuum Aspiration as a Backup for Medical Abortion.

References for this module