Abstract: The third and fourth-degree perineal lacerations are a serious complication of vaginal delivery，and because the laceration involves the anal sphincter complex and/or anal mucous membrane，they are referred to as obstetric anal sphincter injuries（OASIS），which is the most common cause of postpartum anal incontinence and severely affects the quality of life. Accurate assessment of the extent of perineal laceration and timely repair of the anatomy after vaginal delivery is essential to restoring sphincter function and improve prognosis. However，some occult OASIS is sometimes missed and cannot be identified in clinical practice. Unrecognized，unrepaired，or poorly healed OASIS can develop into perineal-rectal fistula or rectal-vaginal fistula. It is necessary to strengthen the prevention and management of OASIS，appropriately apply quality management tools，analyze the risk factors and key aspects leading to OASIS，and develop and implement improvement measures from several key points，such as pregnancy and labor management，assisted delivery capacity enhancement，risk assessment，prevention and treatment，in order to reduce or avoid the occurrence of OASIS while improving the ability to identify and repair OASIS.

Key words: third and fourth-degree perineal lacerations, OASIS, prevention and management

摘要： 会阴Ⅲ～Ⅳ度裂伤是阴道分娩的严重并发症，由于裂伤累及肛门括约肌复合体和（或）肛门黏膜，又称为产科相关肛门括约肌损伤（OASIS），是导致产后肛门失禁最常见的原因，严重影响生活质量。阴道分娩后准确评估会阴裂伤程度并及时修复解剖结构对恢复肛门括约肌功能、改善预后至关重要；但临床实践中隐匿性OASIS有时被漏诊，不能及时识别、修复或愈合不良等，可导致会阴-直肠瘘或直肠-阴道瘘。需要加强预防和管理会阴Ⅲ～Ⅳ度裂伤，恰当运用质量管理工具，分析导致OASIS的风险因素和关键环节，从妊娠期和产程管理、助产能力提升、风险评估、预防和治疗等关键环节着手，减少或避免OASIS发生，提升识别和修复OASIS的能力。

关键词: 会阴Ⅲ～Ⅳ度裂伤, 产科肛门括约肌复合体损伤, 预防和管理