6NICHOLS FH, HUMENICK SS. Childbirth education : Practice, research and theory ( 2nd ed. ) [ J ]. Philadelphia: W. B. Saun- ders ,2000.
7JOHNSON J. Birthball Midwifery Today, 1997,43:59 -65.
8CARRIERE B. The Wiss ball: Theory,basic, exercises and clini- cal application[ J]. New York:Springer.
9KAO BC,GAU ML,WU SF, et al. A comparative study of expect- ant parents childbirth expectations [ J ]. The Journal of Nursing Re- search,2004,12 ( 3 ) : 191 - 202.
10McCARTNEY PR. The new networking. The birth ball are you u- sing it in your practice setting? [ J]. MCN:The American Journal of Maternal Child Nursing. 1998.23 (4) ,218.
5Schlemer G, Gross M, Meyer G. Effectiveness of liberal vs.conservative episiotomy in vaginal delivery with reference to preventing urinary and fecal incontinence: a systematic review [ J ]. Wiener Med Wochenschr, 2003, 153 (11-12) : 269-275.
6Thacker SB, Banta HD. Benefits and risks of episiotomy: an interpretative review of the English language literature, 1860-1980 [J]. Obstet Gynecol Surv, 1983, 38(6) : 322-338.
7Kalis V, l_aine K, De Leeuw JW, et al. Classification of episiotomy: towards a standardisation of terminology [ J]. BJOG, 2012, 119 (5) : 522-526.
9Arulkumaran S. Malpresentation, malposition, cephalopelvic disproportion and obstetric procedures [ A ]//Edmonds DK. Dewhurst' s textbook of obstetrics and gynaecology [ M ]. 8th ed. New Jersey: Wiley-Blackwell, 2012 : 311-325.
10Frankman EA, Wang L, Bunker CH, et al. Episiotomy in the United States: has anything changed? [J]. Am J Obstet Gynecol, 2009, 200(5) : 573. e1-e7.
