1.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.

1.目的本研究色多普勒检测孕妇子宫胎床螺旋动脉搏动（PI），阻力（RI），测妊高征的发生、发展及后。