Department of Obstetrics;
Beijing Obstetrics and Gynecology Hospital;
Capital Medical University;
Beijing 100026;
China;
Department of Obstetrics and Gynecology;
General Hospital of Armed Police Forces;
Beijing 100039;
China;
神经生长因子; 羊水; 脑; 酶联免疫吸附; 试验检测; NGF; 对照组; 妊娠期;