What Happens If the Abortion Pill Doesn’t Work?

When medication abortion fails, the pregnancy either continues with a living embryo or ends incompletely, leaving tissue behind in the uterus. Both situations require follow-up care, and the path forward depends on which type of failure occurred. The distinction matters because an ongoing pregnancy and an incomplete abortion are medically different problems with different solutions. Across large studies, the standard two-drug regimen of mifepristone followed by misoprostol succeeds roughly 95 to 98 percent of the time in early pregnancy, but that still leaves a small number of people facing an outcome they did not expect.

How Often the Abortion Pill Fails

The success rate of medication abortion depends heavily on how far along the pregnancy is. For pregnancies under seven weeks, the two-drug regimen (mifepristone plus misoprostol) produces complete abortion in about 94 to 98 percent of cases.¹ As gestational age climbs past seven weeks, the numbers shift. A meta-analysis of medical abortion trials found that at 50 to 56 days, complete abortion dropped to about 91 percent, and ongoing pregnancy rose to roughly 3 to 5 percent. Beyond eight weeks, mifepristone with misoprostol succeeded about 85 percent of the time.² At 13 weeks and beyond, when medication abortion is used off the standard early-pregnancy protocol, ongoing pregnancy rates rise further, reaching about 10 percent overall in one retrospective study and climbing to 28 percent for pregnancies at 16 weeks or later.³

The combination of mifepristone plus misoprostol is substantially more effective than misoprostol used alone. A randomized trial directly comparing the two found complete abortion in about 97 percent of those who received both drugs versus 76 percent who used misoprostol alone, with ongoing pregnancy in just 1.5 percent of the combination group compared to nearly 17 percent of the misoprostol-only group.⁴ This gap is one reason that mifepristone is considered a critical first step in the regimen. When access to mifepristone is restricted and people use misoprostol on its own, the overall success rate is still high but the risk of needing additional treatment roughly doubles.

Ongoing Pregnancy Versus Incomplete Abortion

The phrase “the pill didn’t work” can mean two different things clinically. The first is an ongoing pregnancy, where the embryo or fetus remains alive and the pregnancy continues to develop. The second is an incomplete abortion, where the pregnancy has ended but tissue remains inside the uterus. Each situation carries different risks and calls for different management.

An ongoing pregnancy after medication abortion is the less common outcome. At early gestational ages, it happens in only about 1 to 3 percent of cases with the standard regimen.² A person with an ongoing pregnancy may still experience some bleeding and cramping from the medications but then notice that pregnancy symptoms like nausea and breast tenderness return or never fully go away. Without follow-up testing, this can be easy to miss in the first days after taking the pills.

Incomplete abortion is more common. The pregnancy has ended, but fragments of tissue remain in the uterus. This can cause prolonged bleeding, cramping, and if left untreated, infection. In a study of patients presenting with complications from incomplete medication abortion, the most frequent symptom was excessive bleeding, reported in nearly 78 percent of cases, and about 8 percent had incomplete abortion complicated by sepsis.⁵ These complications were largely seen in unsupervised settings where people delayed seeking care, which underscores why follow-up is so important.

Warning Signs That Something Is Wrong

After taking misoprostol, bleeding typically starts within one to four hours and the pregnancy tissue usually passes within three to eight hours.⁶ Some bleeding over the following days and weeks is normal. But certain signs suggest something has gone wrong and warrant prompt medical attention:

Heavy bleeding: soaking through more than two pads per hour for longer than two hours.
Persistent pain: cramping that does not improve with pain relievers and prevents normal activities.
Fever: temperature above 38°C (100.4°F) lasting more than 24 hours.
Foul-smelling discharge: yellow or green vaginal discharge, which can signal infection.⁷

The absence of bleeding after taking misoprostol is also concerning. If you experience little or no bleeding, the medication may not have worked at all, and follow-up is essential. On the other end of the spectrum, a study of women who presented late with complications from incomplete abortion found that 63 percent needed a blood transfusion, largely because they underestimated how much blood they were losing and waited too long to seek help.⁸

How Providers Confirm Whether It Worked

Follow-up after medication abortion typically involves checking whether the pregnancy has ended completely. The two main tools are blood tests measuring the pregnancy hormone hCG and ultrasound imaging.

A drop in hCG of 80 percent or more within about a week of taking the medications is a strong indicator that the abortion was complete. In a study of over 500 confirmed complete abortions, nearly 97 percent showed this level of decline. Crucially, none of the ectopic or ongoing pregnancies in the same study showed an 80 percent decline, making this threshold a reliable way to distinguish success from failure.⁹ Semi-quantitative urine pregnancy tests that detect hCG above a certain level have also been explored as a simpler screening tool. One study found that a urine test designed to flag hCG levels above 1,000 IU/L had a sensitivity of about 89 percent for detecting ongoing pregnancy.¹⁰ These at-home tests are less precise than blood draws but can serve as an accessible first check, especially for people who had medication abortions through telemedicine.

Ultrasound plays a role when hCG results are ambiguous or when a provider suspects retained tissue. The appearance of any remaining tissue on ultrasound matters: mass-like residual tissue is more likely to contain chorionic or decidual material that may need intervention, while patchy residual findings are often less clinically significant.¹¹ However, at-home urine testing for follow-up has limitations at later gestational ages. One study concluded that the multi-level urine pregnancy test approach did not reliably work for pregnancies beyond 63 days’ gestation, because hCG levels at those stages are high enough that the test may remain positive even after a successful abortion.¹²

What Happens Next If It Fails

If the abortion pill does not work, there are generally two options: try again with more medication or proceed to a surgical procedure. The choice depends on how far along the pregnancy is, whether the pregnancy is ongoing or incomplete, and what the patient prefers.

For incomplete abortion, a repeat dose of misoprostol is sometimes tried. The results are mixed. One study found that a second round of misoprostol succeeded in only about 47 percent of cases overall, though success was higher among women who were already showing symptoms like bleeding or cramping, where the rate rose to about 64 percent.¹³ When a repeat dose fails or the situation is more urgent, surgical options include vacuum aspiration or dilation and curettage, both of which are highly effective at completing the process.

For an ongoing pregnancy where the embryo still has cardiac activity, medication alone may be attempted again, but providers more often recommend a surgical procedure because of the higher certainty of completion. In rare and complicated scenarios, such as when a pregnancy implants in a cesarean scar, even multiple rounds of medication and manual vacuum aspiration can fail, requiring more invasive surgical intervention.¹⁴

The Hidden Danger of Ectopic Pregnancy

Medication abortion does not treat ectopic pregnancy, a condition where the fertilized egg implants outside the uterus, most commonly in a fallopian tube. This is not a “failure” of the pill in the usual sense; rather, the medication was never going to work because the pregnancy is not in the uterus where mifepristone and misoprostol act. An ectopic pregnancy that goes undiagnosed can be life-threatening.

Distinguishing an ectopic pregnancy from an ongoing intrauterine pregnancy after medication abortion is tricky. Serum hCG trends can help: ectopic pregnancies tend to show rising or slowly declining hCG levels after treatment. In one study, none of the 30 identified ectopic pregnancies showed an hCG decline of 50 percent or more within three to five days. The trends for ectopic pregnancies were clearly different from successful abortions, but could not be reliably distinguished from retained intrauterine pregnancies based on hCG alone.¹⁵ Ultrasound is usually needed to confirm the diagnosis.

A case report from Nepal illustrates how dangerous this situation can become. A woman had taken abortion medications unsupervised three times previously without problems, but her fourth pregnancy was ectopic and located in the cervix. The medications did not terminate it, and the delayed diagnosis led to severe anemia and eventually required an emergency hysterectomy.¹⁶ Similarly, a case series documented several cesarean scar ectopic pregnancies that were misdiagnosed after attempted medical abortion, leading to heavy bleeding, blood transfusions, ICU stays, and in some cases hysterectomy.¹⁷ These are extreme cases, but they highlight why confirming the pregnancy is intrauterine before starting medication is an important safety step.

What If You Continue the Pregnancy After Exposure

Some people who experience a failed medication abortion decide to continue the pregnancy. The question of whether the medications harm the developing embryo or fetus is a serious one, and the evidence is different for misoprostol and mifepristone.

Misoprostol exposure in the first trimester has been linked to a specific pattern of birth defects, particularly a condition called Möbius syndrome (paralysis of certain facial nerves) and limb defects. A systematic review and meta-analysis found that misoprostol exposure roughly tripled the odds of congenital abnormalities overall. The risks for specific conditions were higher: the odds of Möbius syndrome were increased more than 26-fold, and terminal limb defects were increased roughly 11-fold compared to unexposed pregnancies.¹⁸ These are still uncommon in absolute terms since the baseline rates of these conditions are very low, but the relative increase is substantial. A prospective study estimated that about 2 percent of misoprostol-exposed pregnancies showed the specific misoprostol-related malformation pattern, and the overall malformation rate was about 4 percent compared to 1.8 percent in controls.¹⁹ A French study documented major malformations in about 5.5 percent of misoprostol-exposed first-trimester pregnancies, with about half of those malformations fitting the recognized misoprostol pattern.²⁰

The picture for mifepristone alone is more reassuring. A systematic review examining pregnancies that continued after mifepristone exposure found that while congenital anomalies and adverse outcomes were encountered, many of those anomalies could be explained by other factors, and the review did not find data supporting mifepristone itself as a teratogen.²¹ The first prospective study to track pregnancies after mifepristone exposure found that major malformation rates were only slightly above the 2 to 3 percent baseline rate seen in the general population.²² So the teratogenic concern is driven primarily by misoprostol, not mifepristone. Anyone considering continuing a pregnancy after exposure to both drugs should discuss the specific risks with their provider, but the elevated risk is real enough that most clinical guidelines recommend completing the abortion through surgical means if the medication fails.

Does Body Weight Affect Whether It Works

Whether obesity reduces the effectiveness of medication abortion has been debated, and the evidence is somewhat contradictory. A large early study found that women with a BMI above 30 had almost the same rate of needing surgical follow-up as those with a lower BMI: 6 percent versus 5 percent, a difference that was not statistically meaningful.²³ Based on that data, the authors argued that medication abortion should be considered a good option for people with higher body weight, especially given that surgical abortion also carries additional risks in this population.

More recent research, however, suggests the picture is more nuanced. A study comparing obese and non-obese women receiving misoprostol for missed abortion found that the success rate was notably lower in the obese group, about 45 percent versus 69 percent, and the time to complete uterine evacuation was significantly longer.²⁴ A case report of medication abortion failure in a patient with severe (class III) obesity and twin gestation noted that existing studies have not stratified patients by obesity class, instead lumping everyone above a BMI of 30 together, which could mask differences in those with much higher BMIs.²⁵ The practical takeaway is that medication abortion still works for most people regardless of weight, but those with a higher BMI may want to plan for a slightly higher chance of needing a follow-up procedure.

How the Route of Misoprostol Matters

Misoprostol can be taken by several routes: swallowed, placed between the cheek and gum (buccal), or inserted vaginally. The route affects both side effects and success rates, which matters if a first attempt fails and a provider is choosing how to try again.

A large retrospective comparison of vaginal and buccal misoprostol (both after mifepristone) found complete abortion rates of about 96 percent for vaginal and 98 percent for buccal administration for pregnancies under 64 days’ gestation. At later gestational ages (64 to 70 days), the gap narrowed and was no longer statistically significant, with both routes achieving about 93 percent success.²⁶ Earlier randomized trials comparing buccal and vaginal routes showed similar results, with buccal misoprostol performing at least as well as vaginal and sometimes slightly better, though these differences often did not reach statistical significance.²⁷ The buccal route has become increasingly preferred in many clinical settings because it avoids vaginal insertion and allows the person to administer the dose at home easily.

Misoprostol-Only Abortion and Self-Management

In many parts of the world, and increasingly in parts of the United States where mifepristone access is restricted, people use misoprostol alone for self-managed abortion. This approach works, but with a meaningfully higher failure rate than the two-drug combination. A U.S.-based study of self-managed misoprostol-only abortion obtained through an online telemedicine service found that about 88 percent of people reported ending their pregnancy without needing a surgical procedure. About 2 percent reported a serious adverse event, and 4 percent experienced symptoms suggesting a possible complication.²⁸

Self-management raises particular concerns about follow-up. Without a provider relationship, people who experience a failure may not recognize the signs, may delay seeking care, or may avoid the healthcare system altogether, especially in places where abortion is legally restricted. Research on self-managed abortion in legally restrictive settings is scarce, in part because it is difficult to study practices that people may be afraid to disclose.²⁹

Drug Quality and Online Pharmacies

When medications are obtained outside of regulated supply chains, the quality of the pills themselves becomes a variable. A study that purchased mifepristone and misoprostol from online sources and tested their chemical content found that mifepristone tablets were consistently close to their labeled dose. Misoprostol tablets, however, varied wildly: some contained the full 200 micrograms listed on the label, while others contained as little as 34 micrograms, barely a sixth of the intended dose.³⁰ A dose that low is unlikely to be effective, and a person taking it would not know the medication was substandard. This problem is not hypothetical; a review of illegal online pharmacies noted that substandard and falsified medications continue to threaten patient safety, and that historical restrictions on medication access have been linked to increased patient harm from such sources.³¹

For anyone obtaining abortion medications online, the reliability of the source matters enormously. Established telemedicine services that ship from licensed pharmacies are a different situation from unregulated overseas vendors. If the pills do not produce the expected bleeding and cramping, substandard medication quality should be considered as one possible explanation alongside the other medical reasons for failure.

The Emotional Side of a Failed Attempt

A failed medication abortion can be psychologically difficult in ways that go beyond the physical complications. The person has already made a decision, gone through the process of taking the pills, and experienced some of the physical effects, only to learn that the pregnancy persists. This can intensify feelings of anxiety about what comes next, frustration with the process, and distress about needing further intervention. A study of post-abortion care-seeking women found that depression, worry about future fertility, and disordered eating were the most commonly reported psychological consequences, with depression affecting about 60 percent and worry about future fertility affecting about 54 percent of those surveyed. Lower rates of guilt, regret, decreased self-esteem, and nightmares were also reported.³² That study looked at post-abortion populations broadly and not specifically at failed medication abortions, but the general emotional landscape it describes is relevant. The added layer of uncertainty and delayed resolution that comes with a failed attempt can compound these feelings.

Anyone dealing with a failed medication abortion deserves clear information about their options and timely access to the next step of care, whether that is a repeat dose of medication or a surgical procedure. Delays caused by legal barriers, lack of access, or confusion about what is happening medically all tend to make both the physical and emotional experience worse.