The effect of indomethacin on the pulsatility index of the umbilical artery in human fetuses.

Pulsed and continuous-wave Doppler ultrasonography was used to assess blood velocities in the ductus arteriosus and the pulsatility index of the umbilical artery in 20 fetuses (1 pair of twins and 18 singletons) at 23 to 33 weeks' gestation during maternal indomethacin therapy for preterm labor or polyhydramnios. There was no statistically significant difference in the pulsatility index of the umbilical artery during maternal indomethacin treatment (mean +/- SD, 1.11 +/- 0.20) when compared with baseline values (1.12 +/- 0.19) in all 20 fetuses studied. An increase in the peak systolic and diastolic blood velocities in the ductus arteriosus consistent with ductal constriction was noted in 9 fetuses. Analysis of the umbilical artery pulsatility index values before and during indomethacin in this subgroup of fetuses failed to reveal a statistically significant change (1.12 +/- 0.19 vs. 1.11 +/- 0.20). Indomethacin therapy does not influence the pulsatility index of the umbilical artery at the gestational ages studied.