Obstetrics and Gynecology Department, Hospital Universitari Mútua de Terrassa, Plaça Dr. Robert, 4, 08221, Terrassa, Spain.
Obstetrics and Gynecology Department, Hospital Universitari de la Santa Creu i Sant Pau, Barcelona, Spain.
Arch Gynecol Obstet. 2020 Jul;302(1):273-280. doi: 10.1007/s00404-020-05585-4. Epub 2020 May 24.
The objective is to determine the prevalence of levator ani muscle (LAM) avulsion using four-dimensional ultrasound in primiparous women after vaginal delivery and according to delivery mode.
This prospective, multicenter study included 322 women evaluated at 6-12 months postpartum by four-dimensional transperineal ultrasound to identify levator ani muscle avulsion. The researcher who performed the ultrasound was blinded to all clinical data. Meaningful data about the birth were also recorded: mode of delivery, mother's age and body mass index, duration of second stage, episiotomy, perineal tearing, anesthesia, assistant, head circumference and fetal weight.
303 volumes were valid for evaluation. The overall prevalence of levator ani muscle avulsion was 18.8% (95% CI 14.4-23.2%). In our multivariate analysis, only mode of delivery reached statistical significance as a risk factor for levator ani muscle avulsion (p < 0.001). The prevalence according to the different modes of delivery was 7.8% in spontaneous delivery, 28.8% in vacuum-assisted and 51.1% in forceps-assisted delivery. Compared with spontaneous delivery, the OR for LAM avulsion was 12.31 with forceps (CI 95% 5.65-26.80) and 4.78 with vacuum-assisted delivery (CI 95% 2.15-10.63).
Levator ani avulsion during vaginal delivery in primiparous women occurs in nearly one in every five deliveries. Delivery mode is a significant and modifiable intrapartum risk factor for this lesion. The incidence is lower in spontaneous delivery and significantly increases when an instrument is used to assist delivery, especially forceps.
本研究旨在通过四维经会阴超声评估初产妇产后 6-12 个月时肛提肌（LAM）撕裂的发生率，并分析其与分娩方式的关系。
本前瞻性、多中心研究共纳入 322 例初产妇，产后 6-12 个月采用四维经会阴超声评估 LAM 撕裂。行超声检查的研究者对所有临床数据均不知情。同时还记录了与分娩相关的有意义的数据：分娩方式、产妇年龄和 BMI、第二产程时长、会阴侧切、会阴撕裂、麻醉方式、助手、头围和胎儿体重。
303 个有效容积可用于评估。LAM 撕裂的总发生率为 18.8%（95%CI 14.4-23.2%）。多因素分析显示，仅分娩方式是 LAM 撕裂的独立危险因素（p<0.001）。不同分娩方式下 LAM 撕裂的发生率分别为：自然分娩 7.8%、真空辅助分娩 28.8%和产钳助产分娩 51.1%。与自然分娩相比，产钳助产发生 LAM 撕裂的 OR 值为 12.31（95%CI 5.65-26.80），真空辅助分娩的 OR 值为 4.78（95%CI 95% 2.15-10.63）。
初产妇阴道分娩时 LAM 撕裂的发生率接近五分之一。分娩方式是导致该损伤的重要且可改变的产时危险因素。自然分娩时发生率较低，而当使用器械辅助分娩时，尤其是产钳助产，其发生率显著增加。
