Objective To observe pulsative index (PI), resistant index (RI) of placental helicine arteries by colour Doppler, analyses relation between PI, RI and developing of pregnant hypertension.

目的本研彩色多普勒检孕妇子宫胎床螺旋动脉搏动指（PI），阻力指（RI），妊高征的发生、发展及后。