The effects of indomethacin and terbutaline on human fetal umbilical artery velocimetry: A randomized, double-blind study

OBJECTIVE: Our purpose was to study the effects of indomethacin and terbutaline on umbilical artery impedance as measured by the systolic/diastolic ratio. STUDY DESIGN: Normal, low-risk patients at 26 to 32 weeks' gestation were enrolled. A baseline evaluation of the umbilical artery systolic/diastolic ratio was performed. The patients were then randomized to one of three groups and received a coded capsule that contained either terbutaline (5 mg), indomethacin (50 mg), or placebo. Repeat evaluation of the umbilical artery systolic/diastolic ratio was performed 4 hours later. The ratios before and after administration of the medication were compared in the control and study groups. Analysis of variance and paired Student t test were applied. RESULTS: Fifteen patients received indomethacin, 14 placebo, and 12 terbutaline. Pretreatment and posttreatment systolic/diastolic ratios were 3.2 and 3.1 for the indomethacin group, 3.2 and 3.3 for the placebo group, 3.0 and 2.8 for the terbutaline group, respectively. The changes in the systolic/diastolic ratio in the indomethacin and terbutaline groups, as compared with the placebo group, were not found to be significant. CONCLUSION: Terbutaline and indomethacin do not have a significant effect on the human umbilical artery impedance as measured by the systolic/diastolic ratio.