初译
Volume 196, Issue 4, Pages 344.e1-344.e5 (April 2007)
Risk factors for primary and subsequent anal sphincter lacerations: a comparison of cohorts by parity and prior mode of delivery 原发和继发肛门括约肌撕裂伤的危险因素：一组分娩的方式及经产次对照比较
Jerry L. Lowder, MD, MSc1, Lara J. Burrows, MD, MSc1, Marijane A. Krohn, PhD2, Anne M. Weber, MD, MSc1
Received 12 June 2006; received in revised form 21 August 2006; accepted 24 October 2006
Objective This study was performed to assess the effect of pregnancy, route of delivery, and parity on the risk of primary and subsequent anal sphincter laceration in women at first vaginal delivery (1st VD), vaginal birth after cesarean delivery (VBAC), or second vaginal delivery (2nd VD). 目的：在一次阴道分娩（1st VD），剖宫产后的阴道分娩（VBAC）或者二次阴道分娩妇女中，研究评估怀孕期，分娩方式和经产次对原发和继发的肛门括约肌撕裂伤的影响。
Methods This retrospective cohort study used data from a perinatal database that included all deliveries at Magee-Womens Hospital from 1995 to 2002. Anal sphincter laceration was the primary outcome, defined as third- and fourth-degree perineal lacerations. The adjusted odds ratio (OR) for primary and subsequent anal sphincter laceration at delivery by risk group was estimated using logistic regression models and reported with 95% confidence intervals (CIs). 方法：此回顾性队列研究运用围产期资料包括从1995到2002年在Magee妇女医院分娩病例。肛门括约肌撕裂伤为初始结果资料，其被定义为第三和第四度会阴裂伤。对分娩中原发和继发肛门括约肌撕裂伤的风险组采用logistic回归模型和95％可信区间（CIs）评估OR值。
Results We assessed 20,674 live, singleton, term deliveries at Magee-Womens Hospital from 1995 to 2002, including 13,183 with 1st VD, 6068 with 2nd VD, and 1423 with VBAC. Anal sphincter laceration occurred in 16% of women with 1st VD, 18% with VBAC, and 3% with 2nd VD. Multivariable logistic regression modeling for primary anal sphincter laceration showed that 1st VD had OR of 5.1 and 95% CI 4.4, 5.9, and VBAC had OR of 5.1, 95% CI 4.2, 6.2 when compared with the reference group with 2nd VD. Shown in order for 1st VD, VBAC, and 2nd VD, the following factors, adjusted for the other listed factors, were significantly related to anal sphincter laceration except as noted: forceps, ORs of 3.0, 2.6, 5.5; midline episiotomy, ORs of 2.7, 2.9, 2.9; infant birth weight 3500 g or more, ORs of 1.9, 1.9, 1.1, not significantly different from OR of 1.0; vacuum delivery, ORs of 1.7, 1.8, 1.5, not significantly different from OR of 1.0, and 2nd stage of labor 2 hours or longer, ORs of 1.8, 0.9, 0.9, last 2 not significantly different from OR of 1.0. Of women who had anal sphincter laceration in their first vaginal delivery, 7.2% (76 of 1054 women who had 2 pregnancies) had recurrent laceration in their second vaginal delivery, compared with 2.3% (123 of 5147) of women who had a primary anal sphincter laceration in their second vaginal delivery. Multivariable logistic regression modeling for recurrent anal sphincter laceration yielded the following significant factors: episiotomy, OR 8.5, 95% CI 4.1, 17.7; vertex malpresentation (primarily occiput posterior), OR 4.3, 95% CI 1.4, 12.6; shoulder dystocia, OR 2.7, 95% CI 1.2, 5.8; and infant birth weight 3500 g or greater, OR 1.7, 95% CI 1.1, 2.7. 结果：我们评估1995～2002年间Magee 妇女医院中20，674例存活的足月分娩妇女，包括13，183例一次阴道分娩，6068例二次阴道分娩以及1423例剖宫产后阴道分娩。肛门括约肌撕裂伤在一次阴道分娩妇女发生率为16％，在剖宫后的阴道分娩为18％，在二次阴道分娩中为3％。对于原发性肛门括约肌撕裂伤的多元变量logistic 回归模型分析显示以二次阴道分娩为对比参照，一次阴道分娩的OR值为5.1及95％CIs为4.4，5.9，剖宫产后的阴道出生OR值为5.1及95％CIs为4.2，6.2。为显示一次阴道分娩，剖宫产后阴道分娩及二次阴道分娩的影响程度，下列因素经其他所列因子调正显著与肛门括约肌撕裂伤相关： 产钳，OR值分别为3.0，2.6，5.5；正中外阴侧切，OR值为2.7，2.9，2.9；新生儿出生重量为3500g或以上，OR值为1.9，1.9，1.1，其与1.0OR值无显著性差异；vacuum 分娩，OR值为1.7，1.8，1.5，其与1.0OR值无显著性差异，第二产程时间在2小时以上，OR值为1.8，0.9，0.9，后两项与1.0OR值无显著性差异。在一次阴道分娩中存在肛门括约肌撕裂伤的妇女中，在其二次阴道分娩中有7.2％（即1054例第二次怀孕中有76例）可复发撕裂伤，而二次阴道分娩存在原发性肛门撕裂伤为2.3％（即5147例中占123例）。多元变量logistic回归模型分析对于复发性肛门括约肌撕裂伤可归结于以下的重要因素：外阴侧切术，OR值为4.3，95%的可信区间为4.1，17.7；头部先露异常（初为枕后部），OR值为4.3，95%的可信区间为1.4，12.6；肩难产，OR值为2.7，95％的可信区间为1.2，5.8；以及新生儿体重为3500g或更高，OR值为1.7，95%的可信区间为1.1，2.7。
Conclusion At this institution, women undergoing VBAC are at similarly high risk of anal sphincter laceration, compared with nulliparous women. Women with prior anal sphincter laceration are at 3 times increased risk for subsequent sphincter laceration, compared with women with prior vaginal delivery without sphincter laceration. Pregnancy by itself does not appear to be an important factor in decreasing the risk of anal sphincter laceration in subsequent deliveries.结论：通过此研究，经行剖宫产后的妇女对比未经产妇女的肛门括约肌撕裂伤有着类似的高风险。既往有肛门括约肌撕裂伤的妇女其继发括约肌撕裂伤的风险性对比既往无括约肌撕裂伤的增加了3倍。怀孕次数似乎并不能成为减少后来分娩中肛门括约肌撕裂伤风险性的因素。
Key words: anal sphincter laceration, first vaginal delivery, pregnancy, second vaginal delivery, vaginal birth after cesarean delivery 关键词：肛门括约肌撕裂伤，一次阴道分娩，二次阴道分娩，剖宫产后阴道分娩
编译投稿：
据AJOG杂志2007年4月发表的一篇有关怀孕期，分娩方式和经产次对原发和继发的肛门括约肌撕裂伤影响报道中，研究者通过运用回顾性队列研究运用围产期资料包括从1995到2002年在Magee妇女医院分娩病例，对分娩中原发和继发肛门括约肌撕裂伤的风险组采用logistic回归模型和95％可信区间（CIs）评估OR值。最后得出结论：经行剖宫产后的妇女对比未经产妇女的肛门括约肌撕裂伤有着类似的高风险。既往有肛门括约肌撕裂伤的妇女其继发括约肌撕裂伤的风险性对比既往无括约肌撕裂伤的增加了3倍。怀孕次数似乎并不能成为减少后来分娩中肛门括约肌撕裂伤风险性的因素。
