Indocin, known generically as indomethacin, is a medication that may be used during pregnancy in specific medical situations. It belongs to a class of drugs called nonsteroidal anti-inflammatory drugs, or NSAIDs. While typically used for pain and inflammation, its properties allow for careful application in pregnant individuals. Its use in pregnancy is reserved for particular circumstances under close medical supervision.
What is Indocin and Its Role in Pregnancy
Indocin (indomethacin) is a nonsteroidal anti-inflammatory drug (NSAID) that works by inhibiting the production of prostaglandins. These hormone-like substances contribute to inflammation, pain, and fever. In pregnancy, they also play a role in initiating uterine contractions.
This medication may be prescribed during pregnancy for specific conditions, primarily preterm labor and polyhydramnios. In preterm labor, indomethacin acts as a tocolytic, helping to relax the uterus and delay contractions. It is effective in the second and early third trimesters and can be administered orally or intravenously.
Indomethacin can also be used to manage polyhydramnios, a condition characterized by an excessive accumulation of amniotic fluid around the fetus. Indomethacin helps reduce amniotic fluid volume by decreasing fetal urine production by inhibiting prostaglandin synthesis in the fetal kidneys. For these conditions, indomethacin is used for short durations, often 48 to 72 hours, and always under strict medical supervision to monitor both the pregnant individual and the fetus.
Potential Risks to the Fetus
The use of Indocin during pregnancy, particularly in later stages, carries documented risks to the developing fetus. One significant concern is the premature closure of the fetal ductus arteriosus. This blood vessel connects the pulmonary artery to the aorta, allowing blood to bypass the lungs. Prostaglandins normally keep this vessel open before birth. If indomethacin inhibits these prostaglandins, the ductus arteriosus can constrict or close prematurely, leading to increased blood flow to the fetal lungs and potentially causing pulmonary hypertension. This can result in serious heart problems for the newborn.
Another potential adverse effect is fetal renal dysfunction, leading to oligohydramnios (abnormally low levels of amniotic fluid). Indomethacin can reduce the amount of urine the fetus produces by inhibiting fetal renal blood flow, decreasing amniotic fluid volume. Amniotic fluid is important for fetal development, including lung maturation. This reduction is more likely with use extending beyond 48 hours. If oligohydramnios develops, discontinuing the medication usually results in the amniotic fluid volume returning to normal.
Other serious concerns have been reported with indomethacin use in pregnancy. These include an increased risk of necrotizing enterocolitis (a severe intestinal condition), intraventricular hemorrhage (bleeding within the brain, particularly in preterm infants), and platelet dysfunction. The occurrence and severity of these issues are dependent on the timing of administration, dosage, and duration of treatment.
Important Considerations for Pregnant Individuals
When considering indomethacin during pregnancy, healthcare providers typically evaluate the gestational age carefully. Indomethacin is generally considered for use before 32 weeks of gestation, with some guidelines recommending avoidance after 30 weeks. This is because the fetal ductus arteriosus becomes more sensitive to the effects of indomethacin as pregnancy advances, increasing the risk of premature closure in the later third trimester. The United States Food and Drug Administration (FDA) recommends avoiding NSAID use at 20 weeks gestation or later due to the risk of fetal renal dysfunction and subsequent oligohydramnios, and specifically at 30 weeks gestation or later due to the risk of premature closure of the ductus arteriosus.
Certain conditions in the pregnant individual contraindicate the use of indomethacin. These include existing kidney disease, liver disease, asthma, bleeding disorders, or a history of stomach ulcers. The medication should also be avoided in individuals with a recent coronary artery bypass graft (CABG) surgery. Additionally, it is generally not recommended for those attempting to conceive, as it may affect female fertility.
Close medical monitoring is performed during indomethacin treatment to assess both maternal and fetal well-being. This includes regular ultrasounds to check the volume of amniotic fluid and to evaluate fetal cardiac function, specifically the ductus arteriosus. If oligohydramnios occurs, the medication is typically discontinued. Adherence to the prescribed dosage and duration is important, as prolonged use, often beyond 48 to 72 hours, increases the likelihood of fetal side effects. Open communication with healthcare providers is necessary to discuss any concerns or changes experienced during treatment.