Methods The blood flow of umbilical aratery were examined in 30 nomal pregnanceies in latent period by Color Doppler Ultrasonic duing contraction and intermission respectively.

• 方法：采用彩色多普勒超声血流诊断技术，对30例处于潜伏期的孕妇分别进行宫缩期及间歇期脐动脉检测。