6Gibbs Rs.Areriew of premature birth Subchimieal infection[J].Anj obstet Gynecol,1992,166:1515.
7Cox SM. The natuai history of perterm repture membranes:What to expect ofexpectant management. Obstet Gynecol, 1988; 71:558.
8Ernest JM. A prospective randomized placed-controlled trial of penicillin in preterm premature rupture of membranes. Am J Obstet Gynecol, 1994; 170:516.
9Soper DE, Mayhall CG, Dalton HP. Risk factors for intraamniotic infection: A prospective epidemiologic study. Am J Obstet Gynecol,1989; 161(3): 562.