What are the side effects and complications of medication abortion?

Vaginal bleeding and uterine cramping are expected effects of medication abortion methods and are the result of the abortion process. Additionally, there are a number of common side effects associated with the medications used in the medication abortion regimens. The type of side effect and the severity of the side effect varies by regimen. The following table lists the most common side effects reported in selected US trials of medication abortion regimens.[1]

Percentage of women reporting the symptom (by regimen)

Side effect
Mifepristone and misoprostol
Methotrexate and misoprostol
Misoprostol alone
Nausea
36-45%
19-47%
12-43%
Vomiting
13-14%
9-12%
8-45%
Diarrhea
8-11%
7-22%
7-67%
Headache
14-18%
13-16%
12-27%
Dizziness
15-22%
14%
18-37%
Fever, chills warmth, hot flashes
14-20%
15-43%
31-89%

For most women these side effects are tolerable. Many of these side effects can be reduced by using non-prescription pain medications (such as ibuprofen) or anti-emetics (anti-nausea medications).

Complications from medication abortion regimens are relatively rare and include prolonged bleeding, incomplete abortion, and ongoing pregnancy. The rate of complications depends on the specific regimen used. For the mifepristone and misoprostol regimen, approximately 2%-5% of cases will require an aspiration intervention to control bleeding or complete the abortion. About 0.1% of women using the mifepristone and misoprostol regimen will require a transfusion.

For the methotrexate and misoprostol regimen, less than 1% of women will require an intervention for excessive bleeding. For women with pregnancies of seven weeks or less, about 5% will require an aspiration intervention to complete the abortion process.

Of all of the medication abortion regimens, the misoprostol alone regimen carries the greatest risk of complications. When used in the first nine weeks of pregnancy, misoprostol alone has an efficacy of 75%-85%. In approximately 15%-25% of cases, the abortion is incomplete or the pregnancy is ongoing and either an additional dose of misoprostol or an aspiration intervention is required. Recent studies suggest that the ongoing pregnancy rate after administration of misoprostol for early pregnancy termination is approximately 10%. Prolonged or excessive bleeding requiring additional intervention includes in less than 5% of cases.


Reference: ACOG Practice Bulletin. 2001; no. 26.


If you have questions about medication abortion, please visit our page on frequently asked questions.

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Last updated: September 2009