Departments of Obstetrics & Gynecology and Graduate Medical Education, Kaiser Permanente Oakland Medical Center, and the Division of Research, Kaiser Permanente Northern California, Oakland, California; and the Department of Obstetrics & Gynecology, Kaiser Permanente Fremont Medical Center, Fremont, California.
Obstet Gynecol. 2018 Feb;131(2):290-296. doi: 10.1097/AOG.0000000000002444.
To characterize the rate of obstetric anal sphincter injuries and identify key risk factors of obstetric anal sphincter injuries, including duration of the second stage of labor.
This retrospective cohort study included all singleton, term, cephalic vaginal deliveries within Kaiser Permanente Northern California between January 2013 and December 2014 (N=22,741). Incidence of obstetric anal sphincter injuries, defined as third- or fourth-degree perineal lacerations, was the primary outcome. Multiple logistic regression models were conducted to identify obstetric anal sphincter injury risk factors and high-risk subpopulations.
The overall incidence rate of obstetric anal sphincter injuries was 4.9% (3.6% of women who delivered spontaneously vs 24.0% of women who had a vacuum-assisted vaginal delivery, P<.001, CI 18.1-22.6%). In bivariate and multivariate analyses, obstetric anal sphincter injury incidence was higher among women with second stage of labor longer than 2 hours, Asian race, nulliparity, vaginal birth after cesarean delivery, episiotomy, and vacuum delivery. Women with a vacuum-assisted vaginal delivery had four times the odds of obstetric anal sphincter injury (adjusted odds ratio [OR] 4.23, 95% CI 3.59-4.98) and those whose second stage of labor lasted at least 180 minutes vs less than 60 minutes had three times the odds of incurring obstetric anal sphincter injury (adjusted OR 3.20, 95% CI 2.62-3.89).
Vacuum-assisted vaginal delivery conferred the highest odds of obstetric anal sphincter injury followed by prolonged duration of the second stage of labor, particularly among certain subpopulations. Understanding these risk factors and their complex interactions can inform antepartum and intrapartum decision-making with the goal of reducing obstetric anal sphincter injury incidence.
描述产科肛门括约肌损伤的发生率，并确定产科肛门括约肌损伤的关键风险因素，包括第二产程的持续时间。
这是一项回顾性队列研究，纳入了 2013 年 1 月至 2014 年 12 月期间 Kaiser Permanente 北加利福尼亚分校所有单胎、足月、头位阴道分娩产妇（N=22741）。产科肛门括约肌损伤的发生率（定义为三度或四度会阴裂伤）为主要结局。采用多因素逻辑回归模型确定产科肛门括约肌损伤的危险因素和高危亚人群。
产科肛门括约肌损伤的总发生率为 4.9%（自然分娩的产妇中为 3.6%，而使用真空辅助阴道分娩的产妇中为 24.0%，P<.001，CI 18.1-22.6%）。在单因素和多因素分析中，第二产程超过 2 小时、亚洲人种、初产妇、经剖宫产阴道分娩、会阴切开术和使用真空辅助阴道分娩的产妇，其产科肛门括约肌损伤的发生率更高。使用真空辅助阴道分娩的产妇发生产科肛门括约肌损伤的可能性是未使用者的 4 倍（校正比值比[OR] 4.23，95%CI 3.59-4.98），第二产程持续至少 180 分钟与持续不到 60 分钟的产妇相比，发生产科肛门括约肌损伤的可能性增加 3 倍（校正 OR 3.20，95%CI 2.62-3.89）。
真空辅助阴道分娩后产科肛门括约肌损伤的风险最高，其次是第二产程延长，尤其是在某些亚人群中。了解这些风险因素及其复杂的相互作用，可以为产前和产时决策提供信息，以降低产科肛门括约肌损伤的发生率。
