The authors performed a color Doppler ultrasound examination of both renal and interlobar arteries of 15 pregnant women affected by pregnancy-induced hypertension. The pulsatility index (PI), the resistance index (RI) and the systolic/diastol-ic ratio (S/D) values were compared with those of 15 healthy pregnant women of the same gestational age and with those of 15 nonpregnant healthy women. The authors found a significant difference (p < 0.0001) for all parameters investigated in renal and interlobar arteries between healthy pregnant women and the other two groups. No difference was found between patients with pregnancy-induced hypertension and nonpregnant healthy women. In conclusion, color Doppler ultrasound examination of both renal and interlobar arteries seems to be important for understanding the etiopathogenesis of pregnancy-induced hypertension. © 1996 S. Karger AG, Basel.