Objective The perineal body is critical for maintaining the integrity of the pelvic floor, especially in females as it can be injured during vaginal delivery. This study aimed to evaluate the effect of childbirth on perineal body dimensions by using a transperineal 2D ultrasound. Study design This prospective cohort study was performed in a tertiary obstetric care center. A total of 172 term pregnant women who delivered either by cesarean section or vaginal delivery were enrolled in the study. All demographic data and information were collected prospectively. The perineal body was measured in length, height, perimeter, and area. Mode of delivery was classified into four categories, including prelabor cesarean section, cesarean section during the first stage of labor, the first vaginal delivery, and more than one previously vaginal delivery. A postpartum evaluation was performed after 6 weeks. Results Among the 172 women, 40 (23.3 %) had a history of cesarean section (CS) and they delivered with scheduled CS, 40 (23.3 %) women delivered by primary CS during active labor, 48 (27.9 %) women had the first vaginal delivery, 44 (25.6 %) women who delivered vaginally had a history of at least one vaginal delivery. The postpartum perineal body measurements were significantly lower in terms of length, perimeter, and area in all pregnancy groups. Conclusion Pregnancy and delivery change perineal body dimensions, significantly. Cesarean section does not completely protect against changes in perineal body morphology.