3Decherney A H,Nathan L.现代妇产科疾病诊断与治疗[M].9版.刘新民,宋玉琴,万小平,等,译.北京:人民卫生出版社,2004:165.
4Vincenzo B. Obstetric evidence based guidelines[M]. Lon don.. Informa, 2007: 3-16.
5National Institute for Health and Clinical Excellence. Antenatal care= routine care for the healthy pregnant woman[M]. Source London: RCOG Press, 2008 : 1-56.
