Episiotomy and perineal tears: cause and effect CMAJ 1997;157:246 Re: Episiotomy and severe perineal trauma: of science and fiction, by Dr. Michael E. Helewa, CMAJ 1997;156:811-3 [full text / résumé] In response to: M. Labrecque I am mystified by Dr. Labrecque's comments. The editorial does not negate the association between median episiotomy and severe perineal trauma. On the contrary, it promotes a causal relation, on the basis of evidence from the secondary analysis of Klein and colleagues'1 randomized clinical trial. In that secondary analysis it was evident that patients who had an episiotomy accounted for the vast majority of patients suffering third- and fourth-degree tears, regardless of the group (restricted use or liberal use of episiotomy) to which they were originally allocated. However, I went a step further and posed the following question: Would adopting a policy of restricting episiotomy result in a reduction in the incidence of third- and fourth-degree tears? According to the evidence from the 2 major randomized clinical trials discussed in my editorial and from other minor randomized trials available in the literature, this desired effect might not materialize. In the 2 trials conducted in Canada and Argentina, there was no significant difference in incidence of perineal trauma between the restricted-episiotomy and the liberal-episiotomy groups.2,3 The reasons for this observation are simple. First, a large number of physicians perform an episiotomy for perceived indications at the time of delivery, even if a selective or restrictive policy is advised. In Klein and colleagues'2 randomized clinical trial, more than 50% of primigravid patients randomly assigned to the restricted-episiotomy group still underwent an episiotomy. Second, there are many risk factors other than episiotomy that may lead to severe perineal trauma. Labrecque and colleagues have shown that birth weight, forceps use and gestational age are independent risk factors associated with third- and fourth-degree tears. Others have suggested that shoulder dystocia or birth position are risk factors. Labrecque criticizes the classification of the research designs presented in the editorial. This classification is not unique but has been published extensively in the past, especially by Thacker and Banta4 and Woolley.5 I agree with Labrecque that a cross-sectional study is a prevalence study. However, this study design was commonly used in the early articles on the topic. Authors attempted to establish a relation between episiotomy and severe perineal lacerations through the use of this design. A significant number of these early articles also failed to indicate the type of episiotomy (mediolateral or median) performed. In the cross-sectional studies in which the type of episiotomy was addressed, however, severe perineal trauma was more prevalent in women who sustained a median episiotomy. Labrecque's comments downplay the importance of randomized clinical trials in establishing causality. Cohort retrospective studies establish associations. Strong associations may imply causality. Still, the 2 are not the same. Fortunately, however, randomized clinical trials concerning episiotomy and its effect on trauma have been performed successfully, despite the inherent difficulties encountered in such a study design. If Labrecque takes another look at the editorial his perceptions of what I presented may change. He may realize that the ideas promoted in my editorial are those of a friend, not a foe, to his good work. Michael E. Helewa, MD Head Clinical Obstetrics St. Boniface General Hospital Associate Professor University of Manitoba Winnipeg, Man. References Klein MC, Kaczorowski J, Robbins JM, Gauthier RJ, Jorgensen SH, Joshi AK. Physicians' beliefs and behaviour during a randomized controlled trial of episiotomy: consequences for women in their care. CMAJ 1995;153:769-79. Klein MC, Gauthier RJ, Jorgensen SH, Robbins JM, Kaczorowski J, Johnson B, et al. Does episiotomy prevent perineal trauma and pelvic floor relaxation? [article]. Online J Curr Clin Trials 1992;Jul 1(doc 10)[6019 words]. Argentine Episiotomy Trial Collaborative Group. Routine vs selective episiotomy: a randomised controlled trial. Lancet 1993;342:1517-8. Thacker SB, Banta HD. Benefits and risks of episiotomy: an interpretive review of the English language literature, 1960­1980. Obstet Gynecol Surv 1983;38:322-38. Woolley RJ. Benefits and risks of episiotomy: review of the English-language literature since 1980 [2 parts]. Obstet Gynecol Surv 1995;50:806-35. Send a letter to the editor responding to this letter Envoyez une lettre à la rédaction au sujet de cette lettre | CMAJ August 15, 1997 (vol 157, no 4) / JAMC le 15 août 1997 (vol 157, no 4) |