The step by step regression analysis showed that D and S/D of UA, S and RI of MCA, S of AA and RI of UTA had a close correlation with gestation.

• 逐步回归分析显示 U A的 D和 S/D、MCA的 S和 RI、AA的 S及 UTA的 RI等参数与孕周关系密切。