Health Library Indomethacin for Slowing Preterm LaborFrom Healthwise

Indomethacin is sometimes used as a tocolytic medication 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).

Use of indomethacin for the treatment of preterm labor is an unlabeled use of the drug. Indomethacin is usually used as an anti-inflammatory medication to treat arthritis and other conditions that can affect joints and tissues around joints.

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

Indomethacin is used only:

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

Indomethacin can be used for the treatment of 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 medications (ritodrine and terbutaline) have not stopped uterine contractions.
• The mother is at high risk of suffering the side effects of beta-sympathetic medications (ritodrine and terbutaline) due to such conditions as diabetes, heart disease, or lung disease.¹
• Treatment with other tocolytic medications was stopped because of side effects.

Indomethacin can be effective in delaying preterm labor for up to 48 hours.² More research is needed before its harms and benefits are fully known.

Indomethacin appears to have fewer side effects on the mother but potentially more serious effects on the fetus than other tocolytic medications used to treat preterm labor. However, fetal side effects are very unlikely when treatment lasts fewer 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.)

• 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 testing on the mother are used to check the amount of amniotic fluid.

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Citations

1. Dyson DC, et al. (1998). Monitoring women at risk for preterm labor. New England Journal of Medicine, 338(1): 15–19.

2. Haas DM (2005). Preterm birth, search date June 2005. Online version of Clinical Evidence (14): 1–20.

Author:	Kathe Gallagher, MSW	Last Updated: January 19, 2007
Medical Review:	Joy Melnikow, MD, MPH - Family Medicine Kathleen Romito, MD - Family Medicine William Gilbert, MD - Perinatology
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