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.

目的本研究采用普勒检测孕妇子宫胎床螺旋动脉搏动数（PI），数（RI），预测妊高征的发生、发展及预后。