There is increased focus on obstetric anal sphincter injury (OASI) and there are several well-established risk factors such as birthweight, instrumental delivery and median episiotomy. Some studies have found increased risk of OASI in women delivering vaginally after a previous caesarean section (VBAC).

中文翻译：

---

剖腹产后阴道分娩妇女产科肛门括约肌损伤风险增加：一项系统评价和荟萃分析

人们越来越关注产科肛门括约肌损伤 (OASI)，并且有几个公认的风险因素，例如出生体重、器械分娩和会阴正中切开术。一些研究发现，在先前的剖腹产 (VBAC) 后阴道分娩的妇女发生 OASI 的风险增加。