Department of Obstetrics & Gynaecology, Faculty of Medicine, The Chinese University of Hong Kong, Hong Kong.
Ultrasound Obstet Gynecol. 2012 Jun;39(6):704-9. doi: 10.1002/uog.10132. Epub 2012 May 7.
To assess the prevalence of levator ani muscle injury in Chinese women after their first delivery and investigate associated factors.
A prospective observational study was conducted involving Chinese nulliparous women recruited in the first trimester of pregnancy. Translabial ultrasound was performed at 35-38 weeks' gestation and 8 weeks postpartum and three-dimensional volume datasets were obtained. Offline analysis to detect levator ani muscle injury was performed by investigators blinded to the delivery details.
339 women, with a mean age of 30.6 ± 3.9 years, completed the study. Overall, 201 (59.3%) had a spontaneous vaginal delivery, 62 (18.3%) an operative vaginal delivery (48 ventouse extraction and 14 forceps delivery), 14 (4.1%) an elective Cesarean section and 62 (18.3%) an emergency Cesarean section. No levator ani muscle injury was detected in any woman antenatally. After vaginal delivery, 57 (21.7% (95% CI, 16.7-26.7%)) women had levator ani muscle injury. The rates of injury for spontaneous vaginal delivery, ventouse extraction and forceps delivery were 15.4%, 33.3% and 71.4%, respectively. There was no levator ani muscle injury in the Cesarean section groups. Logistic regression analysis showed that only operative vaginal delivery (odds ratio, 3.09) was associated with an independent increase in the likelihood of levator ani muscle injury. Intrapartum epidural analgesics, duration of second stage of labor and infant birth weight were not independently associated with levator ani muscle injury.
The prevalence of levator ani muscle injury in Chinese women after their first vaginal delivery was 21.7% (95% CI, 16.7-26.7%). Operative vaginal delivery was found to increase the likelihood of women suffering such injury. A longer follow-up of these women and future studies on the effects of episiotomy are proposed.
评估中国初产妇产后第一产程中肛提肌损伤的发生率，并探讨相关因素。
前瞻性观察性研究，纳入妊娠早期的中国初产妇。于 35-38 孕周及产后 8 周行经阴道超声检查，获取三维容积数据集。由不了解分娩细节的研究者进行离线分析以检测肛提肌损伤。
339 名平均年龄 30.6±3.9 岁的女性完成了研究。总体而言，201 名（59.3%）为自发性阴道分娩，62 名（18.3%）为阴道助产分娩（48 例产钳助产，14 例胎头吸引术），14 名（4.1%）为选择性剖宫产，62 名（18.3%）为紧急剖宫产。任何女性在产前均未发现肛提肌损伤。阴道分娩后，57 名（21.7%（95%CI，16.7%-26.7%））女性发生肛提肌损伤。自发性阴道分娩、产钳助产和胎头吸引术的损伤发生率分别为 15.4%、33.3%和 71.4%。剖宫产组均无肛提肌损伤。Logistic 回归分析显示，仅阴道助产分娩（比值比，3.09）与肛提肌损伤的发生独立相关。产程中硬膜外镇痛、第二产程时长和婴儿出生体重与肛提肌损伤无独立相关性。
中国女性首次阴道分娩后肛提肌损伤的发生率为 21.7%（95%CI，16.7%-26.7%）。阴道助产分娩可增加女性发生此类损伤的可能性。建议对这些女性进行更长时间的随访，并进一步开展关于会阴切开术影响的研究。
