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Indomethacin for Slowing Preterm Labor


Generic Name Brand Name
indomethacin Indocin

Indomethacin is sometimes used as a tocolytic medicine to prolong pregnancy by slowing preterm uterine contractions.

Indomethacin is given through a vein (intravenously), by mouth as capsules or liquid (orally), or in the rectum (anal suppository).

How It Works

Indomethacin is a nonsteroidal anti-inflammatory drug (NSAID) that blocks the production of certain substances called prostaglandins, which contribute to uterine contractions.

Why It Is Used

Indomethacin is used only:

  • For short-term treatment of preterm labor.
  • Before 31 to 32 weeks of pregnancy.

Indomethacin can be used to treat preterm labor when:

  • Labor needs to be delayed for 24 to 48 hours to:
    • Let corticosteroids given to the mother help fetal lungs mature.
    • Provide time to move a mother to a hospital that provides neonatal intensive care, if her local hospital does not.
  • Regular contractions of the uterus have thinned the cervix less than 80% and opened it less than 4 cm, and the mother's amniotic sac has not broken.
  • Beta-sympathetic medicines (such as terbutaline) have not stopped uterine contractions.
  • Treatment with other tocolytic medicines was stopped because of side effects.

How Well It Works

Indomethacin can be effective in delaying preterm labor.1 More research is needed before its harms and benefits are fully known.

Side Effects

Indomethacin appears to have fewer side effects on the mother but potentially more serious effects on the fetus than other tocolytic medicines used to treat preterm labor. But fetal side effects are very unlikely when treatment lasts less than 7 days. Indomethacin may cause:

  • A fetus's kidneys to produce abnormally low amounts of urine, resulting in a decrease in the amount of amniotic fluid (oligohydramnios).
  • Early changes in the heart that do not normally occur until after birth. This may cause problems with fetal blood circulation.

Maternal side effects are very rare. They include:

  • Headaches.
  • Dizziness.
  • Nausea and/or vomiting.
  • Stomach upset or heartburn.
  • Prolonged vaginal bleeding.

See Drug Reference for a full list of side effects. (Drug Reference is not available in all systems.)

What To Think About

  • Indomethacin is used with caution, particularly for pregnant women with heart disease, asthma, a history of intestinal bleeding or ulcers, kidney disease, problems with blood clotting, or a decreased amount of amniotic fluid (oligohydramnios). It is also not used during the last 2 months of pregnancy because of possible effects on fetal heart development.
  • When indomethacin is used for more than 3 to 7 days, fetal monitoring with an echocardiogram and regular ultrasound tests on the mother are used to check the amount of amniotic fluid.

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  1. Haas DM (2011). Preterm birth, search date June 2010. BMJ Clinical Evidence. Available online:


By Healthwise Staff
Primary Medical Reviewer Sarah Marshall, MD - Family Medicine
Specialist Medical Reviewer William Gilbert, MD - Maternal and Fetal Medicine
Last Revised January 8, 2013

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