Recovery of puborectalis muscle after vaginal delivery: an ultrasound study.

OBJECTIVES: To assess change in levator hiatal dimensions between pregnancy and different timepoints after vaginal delivery, and map recovery of the hiatus in order to contribute to secondary prevention of symptoms of pelvic floor disorders.

METHODS: Twenty nulliparous women with a singleton pregnancy underwent ultrasound assessment of the pelvic floor at rest, on maximum pelvic floor muscle contraction (PFMC) and on Valsalva maneuver at 12 weeks' gestation and at 1 day and 1, 2, 3, 4, 6, 12, 18 and 24 weeks after vaginal delivery. Dimensions of the levator hiatus were measured and contractility and distensibility were calculated. The Wilcoxon signed rank test was used to compare each postpartum value with that at 12 weeks' gestation.

RESULTS: Levator hiatal area at rest, on PFMC and on Valsalva maneuver was significantly increased at 1 day and at 1 and 2 weeks after vaginal delivery compared with measurements at 12 weeks' gestation. Hiatal area at rest and on PFMC from 3 weeks postpartum onward, as well as contractility from 6 weeks onward, were comparable to values at 12 weeks' gestation, whereas, a significant difference remained on Valsalva maneuver until 24 weeks after delivery. Moreover, distensibility was still increased at 24 weeks postpartum compared with measurements at 12 weeks' gestation.

CONCLUSION: The puborectalis muscle has the ability to recover anatomically from a first vaginal delivery, and recovery occurs mainly during the first 3 weeks after delivery. Stretching of the puborectalis muscle, as reflected by distensibility, persisted 24 weeks after the first vaginal delivery. The data provide a better understanding of the early 'normal' regeneration process and we hypothesize that the first 3 weeks postpartum is the best window in which to start secondary prevention. Copyright © 2017 ISUOG. Published by John Wiley & Sons Ltd.