How It Works
Misoprostol:
- Softens and opens (dilates) the
cervix.
- Causes uterine contractions.
- Starts (induces)
labor.
Why It Is Used
Misoprostol is a
prostaglandin medicine used to terminate a pregnancy
by starting labor. It is more effective when used in combination with
methotrexate or mifepristone than when used alone. This is an
unlabeled use of misoprostol.
Misoprostol
is also used to prevent stomach ulcers (labeled use) and for induction of labor
for childbirth (unlabeled use).
Misoprostol may also be used to:
- Complete a spontaneous missed abortion
(incomplete miscarriage).
- Start labor in second-trimester
abortions.
- Start labor
in third-trimester abortions. Third-trimester abortions are not done unless the fetus has
died or has severe medical problems and will not survive.
- Dilate
the cervix 3 to 4 hours before a surgical abortion
procedure.
- Soften the cervix for induction of
labor.
- Soften the cervix for special gynecologic tests.
How Well It Works
Misoprostol used alone may terminate
a pregnancy. But it is more often used with other medicines, such as
mifepristone or methotrexate, in first-trimester
abortions.
Misoprostol alone, moistened and used
vaginally, is effective in over 90 out of 100 cases in terminating first-trimester pregnancies of
less than 8 weeks.1
Misoprostol can be given orally, buccally (dissolved between the gums and cheek), or vaginally. Misoprostol
is slightly more effective when taken vaginally than when taken by
mouth.1 But many doctors are only giving misoprostol by mouth because of reports of a rare, fatal infection that affected a few women after using vaginal misoprostol. Some studies have shown that taking misoprostol buccally works as well as when it is given vaginally or orally.2, 3
Side Effects
This method of abortion causes symptoms
similar to a
miscarriage (such as severe cramping and vaginal
bleeding) as tissue and clots pass from the uterus. Symptoms may
include:
- Nausea.
- Vomiting.
- Diarrhea.
- Headache.
- Dizziness.
- Chills
or hot flushes (sweating and feeling overly
hot).
- Shivering.
- Fatigue.
The U.S. Food
and Drug Administration (FDA) has reported that a few women have died from a
severe infection (sepsis) after having an abortion using
mifepristone and vaginal misoprostol.4 Signs of serious infection include
weakness, nausea, and diarrhea with or without belly pain. This rare
infection may not cause a fever. Call your doctor or go to the hospital if you
have any of these signs of a serious infection after having a medical
abortion.
Signs of complications
Call your doctor immediately if you have any of these symptoms after an abortion:
- Severe bleeding. Both medical and surgical
abortions usually cause bleeding that is different from a normal menstrual
period. Severe bleeding can mean:
- Passing clots that are bigger than a
golf ball, lasting 2 or more hours.
- Soaking more than 2 large pads
in an hour, for 2 hours in a row.
- Bleeding heavily for 12 hours in
a row.
- Signs of infection in your whole body, such as
headache, muscle aches, dizziness, or a general feeling of illness. Severe
infection is possible without fever.
- Severe pain in the belly
that is not relieved by pain medicine, rest, or heat
- Hot flushes or a fever of
100.4°F (38°C) or higher that
lasts longer than 4 hours
- Vomiting lasting more than 4 to 6
hours
- Sudden belly swelling or rapid heart
rate
- Vaginal discharge that has increased in amount or smells
bad
- Pain, swelling, or redness in the genital area
Call your doctor for an appointment if you have had any of these symptoms after a recent
abortion:
- Bleeding (not spotting) for longer than 2
weeks
- New, unexplained symptoms that may be caused by medicines
used in your treatment
- No menstrual period within 6 weeks after the
procedure
- Signs and symptoms of
depression. Hormonal changes after a pregnancy can
cause depression that requires treatment.
See Drug Reference for a full list of side effects.
(Drug Reference is not available in all systems.)
What To Think About
Choosing a medical or surgical
procedure for an abortion will depend on your past health, how many weeks
pregnant you are, what options are available where you live, and your personal
preferences.
Misoprostol is not used in women who have an allergy
to misoprostol or other prostaglandins.
Misoprostol can cause
fetal abnormalities, so a follow-up surgical abortion will be done if the medical abortion did not work.
The use of misoprostol for medical
abortion is an unlabeled use. Misoprostol is approved (labeled) for preventing
and treating
stomach ulcers in people taking nonsteroidal
anti-inflammatory drugs (NSAIDs) on a long-term schedule.
Misoprostol does not have any known drug interactions.
Unlike other prostaglandins, misoprostol does not increase the risk of a
heart attack or
bronchospasm.
Complete the new medication information form (PDF)(What is a PDF document?) to help you understand this medication.
References
Citations
-
American College of Obstetricians and Gynecologists
(2005, reaffirmed 2009). Medical management of abortion. ACOG Practice Bulletin
No. 67. Obstetrics and Gynecology, 106(4):
871–882.
-
Middleton T, et al. (2005). Randomized trial of
mifepristone and buccal or vaginal misoprostol for abortion through 56 days of
last menstrual period. Contraception, 72(5):
328–332.
-
Winikoff B, et al. (2008). Two distinct oral routes of misoprostol in mifepristone medical abortion: A randomized controlled trial. Obstetrics and Gynecology, 112(6): 1303–1310.
-
U.S. Food and Drug Administration (2006). Public health advisory: Sepsis and medical abortion with mifepristone (Mifeprex). Available online: http://www.fda.gov/Drugs/DrugSafety/PublicHealthAdvisories/ucm051298.htm.
Credits
|
By
|
Healthwise Staff |
|
Primary Medical Reviewer
|
Sarah Marshall, MD - Family Medicine |
|
Specialist Medical Reviewer
|
Rebecca H. Allen, MD, MPH - Obstetrics and Gynecology |
|
Specialist Medical Reviewer
|
Kirtly Jones, MD - Obstetrics and Gynecology |
|
Last Revised
|
August 31, 2012 |
American College of Obstetricians and Gynecologists
(2005, reaffirmed 2009). Medical management of abortion. ACOG Practice Bulletin
No. 67. Obstetrics and Gynecology, 106(4):
871–882.
Middleton T, et al. (2005). Randomized trial of
mifepristone and buccal or vaginal misoprostol for abortion through 56 days of
last menstrual period. Contraception, 72(5):
328–332.
Winikoff B, et al. (2008). Two distinct oral routes of misoprostol in mifepristone medical abortion: A randomized controlled trial. Obstetrics and Gynecology, 112(6): 1303–1310.
U.S. Food and Drug Administration (2006). Public health advisory: Sepsis and medical abortion with mifepristone (Mifeprex). Available online: http://www.fda.gov/Drugs/DrugSafety/PublicHealthAdvisories/ucm051298.htm.