Pihl S, et al. - In this prospective observational study of 150 primiparous women performed at the University Hospital, Linköping, Sweden, researchers evaluated how the anovaginal distance (AVD) measured with transperineal ultrasound immediately after delivery is related with external anal sphincter injury. In addition, they assessed the association of the palpated perineal thickness with the AVD. In accordance to standard care, perineal laceration diagnosis was done. Compared with women without anal sphincter injury, women with an external sphincter injury had a shorter AVD and shorter palpatory perineal thickness. Women with the AVD and/or palpation height of ≥ 20 mm experienced no external sphincter injuries. The mean AVD in the group with probable second-degree laceration (n = 85) was 18.8 mm, in suspected third-degree laceration (n = 33) was 15.7 mm and in probable third-degree laceration (n = 32) was 11.8 mm. Findings thus suggest a short AVD as a warning sign postpartum and should increase the awareness of possible external sphincter injury before suturing.