Indomethacin for preterm labor: fetal toxicity in a dizygotic twin gestation.

Indomethacin was given for the treatment of preterm labor in a twin pregnancy at a dosage of 200 mg/day for 7 days beginning at 34 weeks and 5 days' gestation. During treatment, one twin developed closure of the ductus arteriosus, tricuspid regurgitation, right ventricular dysfunction, and pericardial effusion. Severe oligohydramnios in both amniotic sacs appeared as well. All findings resolved within 7 days of discontinuation of the medication. The infants, delivered vaginally at 37 weeks' gestation, were alive and well at a 2-month follow-up visit. We believe that all fetuses of mothers treated with indomethacin should be closely monitored for early evidence of decreased amniotic fluid volume and constriction of the ductus arteriosus.