6Szpakowski A,Malinowski A,Zeman K et al.The influence of patemal lymphocytes immunization on percentage of peripheral blood CD 16^+/CD 56^+ cells in wumen with primary recurrent spontaneous abortion.Ginekol-Pol,2001,72(12):1063
7Cunningham FG, Leveno K J, Bloom SL, et al. Williams Obstet- rics[ M ]. 22nd edition. London : McGraw-Hill Medical, 2005 : 222.
8Rand L, Norwitz ER. Current controversies in cervical cerclage [ J]. Semin in Perinatol,2003,27( 1 ) :73-85.
9Abenhaim HA, Tulandi T. Cervical insufficiency : re-evaluating the prophylactic cervical cerclage [ J ]. J Matem Fetal Neonatal Med,2009,22 (6) :510-516.
10Shennan A, Jones B. The cervix and prematurity: aetiology,pre- diction and prevention [ J]. Semin Fetal Neonatal Med, 2008,9 (6) :471-479.
