After about 36 weeks to determine how much amniotic fluid and placentalfunction.
怀孕晚期大约36周以后，以确定羊水多少以及胎盘的功能。
2
To study the relation between placental mature grading and placentalfunction to improve the method of monitoring placentalfunction.
探讨孕妇胎盘成熟度分级与胎盘功能之间的联系，以提供更多监测胎盘功能的方法。
3
Objective To evaluate the placentalfunction and predict the pregnancy outcome by studying the relation between ultrasound placental mature grading and the pathology changes of the placenta.