4McCandlish R, Bowler U,Van Asten H,et al. A randomised con- trolled trial of care of the perineum during second stage of normal labour[ J ]. Br J Obstet Gynaecol, 1998,105 (12) : 1 262-1 272.
5Aasheim V, Nilsen AB, Lukasse M, et al. Perineal techniques during the second stage of labour for reducing perineal trauma[ J ]. Cochrane Database Syst Rev, 2011 (12) : 6 672.
6Mayerhofer K, Bodner-Adler B, Bodner K, et al. Traditional care of the perineum during birth:a prospective,randomized,multicenter study of 1 076 women [ J .J Reprod Med, 2002,47 (6) : 477-482.
7De Souza CDCA,Gonzalez RM. A comparison of "hands off" versus "hands on" techniques for decreasing perineal lacerations during birth [ J ]. J Midwifery Womens Health, 2006,51 (2) : 106 - 111.