The effect of a normal vaginal delivery on anal function

BACKGROUND: To determine the effect of an uncomplicated vaginal delivery on anal sphincter function in primiparous women. METHODS: In a prospective study, anal manometry was performed prenatally and at 4-6 weeks postnatally in 18 primiparous women (11 undergoing vaginal delivery; seven having Cesarean section). No patient had any evidence of anal sphincter damage after delivery as determined by anal ultrasound and pudendal nerve terminal motor latency. RESULTS: Vaginal delivery was associated with a significant reduction in the squeeze pressure (SP: prenatal 269 cm H2O vs postnatal 204 cm H2O; p=0.004) but not the resting pressure (RP: prenatal 96 cm H2O vs postnatal 86 cm H2O; p=0.075). Cesarean section was not associated with any significant change in anal pressures. CONCLUSION: A normal vaginal delivery with no evidence of sphincter injury was associated with a significant effect on anal function when measured 4-6 weeks postnatally.