4Andreeva A, Marinov B. Midtrimester pregnancy termination- contemporary methods and techniques [J]. Akush Ginekol, 2011,50(4):35- 41.
5Islam A, Abbasi Au, Sarwar I. Use of Foley's catheter and prostaglandin F-2 alpha in second trimester termination of pregnancy[J]. J Ayub Med Coll Abbottahad, 2006,18 ( 3 ) : 35- 39.
5Newmann SJ, Dalve-Endres A, Diedrich JT, et al. Cervical preparation for second trimester dilation and evacuation [J]. Cochrane Database Syst Rev, 2010,4(8) : CD007310.
6Bakour SH,Thompson PK,Khan KS. Successful conser- vative management of cervical ectopic pregnancy with combination of methotrexate, mifepristone, surgical evacu- ation and tamponade using a double balloon three-way catheter[J]. J Obstet Gynaecol,2005,25(6):616-618.
7Summers L. Methods of cervical ripening and labor in- duction[J]. J Nurse Midwifery, 1997,42(2):71-85.
