['Prophylactic indomethacin reduces severe intraventricular hemorrhage and symptomatic patent ductus arteriosus in premature infants. The purpose of this study was to investigate the effects of prophylactic low-dose indomethacin on renal and intestinal blood flow.', 'Subjects were 19 extremely low-birthweight infants admitted to our hospital and enrolled in a multicenter randomized control trial to study the efficacy and complications of prophylactic low-dose indomethacin in the reduction of severe intraventricular hemorrhage and patent ductus arteriosus (indomethacin and placebo groups, ten and nine infants, respectively). We measured blood flow velocity in the right renal artery (right RA) and superior mesenteric artery (SMA) with pulsed Doppler ultrasound before and after the administration of the first dose of 0.1 mg/kg indomethacin or placebo.', 'End-diastolic blood flow velocity (EDV) in the right RA and SMA increased significantly after the administration of indomethacin (P = 0.0414 and 0.0284, respectively), although the time-averaged mean blood flow velocity (TAV) did not change significantly in either artery. In the placebo group, the pre- and postadministration values for TAV and EDV in the right RA and SMA did not differ. Neither group showed a significant change in the relative vascular resistance (mean blood pressure/TAV) in the right RA or SMA. EDV in the left pulmonary artery was significantly reduced only after the administration of indomethacin (P = 0.0284).'] Does effects of prophylactic indomethacin on renal and intestinal blood flow in premature infants?