Perineal Trauma in a Low-risk Maternity with High Prevalence of Upright Position during the Second Stage of Labor

Abstract Objective Perineal trauma is a negative outcome during labor, and until now it is unclear if the maternal position during the second stage of labormay influence the risk of acquiring severe perineal trauma. We have aimed to determine the prevalence of perineal trauma and its risk factors in a low-risk maternity with a high incidence of upright position during the second stage of labor. Methods A retrospective cohort study of 264 singleton pregnancies during labor was performed at a low-risk pregnancymaternity during a 6-month period. Perineal trauma was classified according to the Royal College of Obstetricians and Gynecologists (RCOG), and perineal integrity was divided into three categories: no tears; first/ second-degree tears + episiotomy; and third and fourth-degree tears. A multinomial analysis was performed to search for associated factors of perineal trauma. Results From a total of 264 women, there were 2 cases (0.75%) of severe perineal trauma, which occurred in nulliparous women younger than 25 years old. Approximately 46% (121) of the women had no tears, and 7.95% (21) performed mediolateral episiotomies. Perineal trauma was not associated with maternal position (p = 0.285), health professional (obstetricians or midwives; p = 0.231), newborns with 4 kilos or more (p = 0.672), and labor analgesia (p = 0.319). The multinomial analysis showed that white and nulliparous presented, respectively, 3.90 and 2.90 times more risk of presenting perineal tears. Conclusion The incidence of severe perineal trauma was low. The prevalence of upright position during the second stage of labor was 42%. White and nulliparous women were more prone to develop perineal tears.

摘要 目的 会阴创伤是分娩期间的不良妊娠结局，目前尚不明确分娩第二产程的产妇体位是否会影响严重会阴创伤的发生风险。本研究旨在明确低危产科人群中，分娩第二产程采用高比例直立体位时的会阴创伤患病率及其危险因素。方法 本研究为回顾性队列研究，纳入某低危产科中心6个月内收治的264例单胎妊娠分娩产妇。会阴创伤参照英国皇家妇产科医师学院（Royal College of Obstetricians and Gynecologists, RCOG）标准进行分类，会阴完整性分为三类：无裂伤；Ⅰ/Ⅱ度裂伤+会阴切开术；Ⅲ、Ⅳ度裂伤。采用多项分析探究会阴创伤的相关影响因素。结果 264例产妇中，共2例（0.75%）发生严重会阴创伤，均见于25岁以下的初产妇。约46%（121例）的产妇无会阴裂伤，7.95%（21例）接受了会阴侧斜切开术。研究显示，会阴创伤与产妇体位（p=0.285）、接生医护人员（产科医师或助产士；p=0.231）、新生儿出生体重≥4kg（p=0.672）以及分娩镇痛（p=0.319）均无显著关联。多项分析结果表明，白种产妇与初产妇发生会阴裂伤的风险分别为其他产妇的3.90倍和2.90倍。结论 严重会阴创伤的发生率较低。分娩第二产程中采用直立体位的产妇占比为42%。白种产妇与初产妇更易发生会阴裂伤。