A total number of 207 women were included in the study. There was no information available about whether the women declined participation or if they were not invited to participate. 333 women were excluded due to prematurity, cervix dilatation > seven cm when the women were signed in at the delivery ward, younger than 18 years or not speaking satisfactory Swedish language. After woman's informed consent, the AVD was measured with transperineal ultrasound. The standardized method consisted of placing the vaginal probe at a right angle to the posterior vaginal distal wall, and in a transversal scanning plane. All examinations were done with the patient in the lithotomy position. The internal anal sphincter was detected as a low-echogenic ring when the probe was moved cranially from the distal anal canal to the mid anal canal. The AVD in this study was measured and defined as the distance between the anal mucosa and the vaginal wall at the middle level of the anal canal. The measured AVD, in millimeters (mm), was documented in the women´s medical record under a specific keyword named "anovaginal distance".