Postpartum pelvic floor muscle training, levator ani avulsion and levator hiatus area: a randomized trial

Abstract

Introduction and hypothesis: Vaginal delivery may lead to tearing of the levator ani (LA) muscle from its bony insertions (complete LA avulsion) and increased levator hiatus (LH) area, both risk factors for pelvic floor dysfunctions. Early active rehabilitation is standard treatment after musculo-skeletal injury. We hypothesized that pelvic floor muscle training (PFMT) early postpartum would reduce the presence of LA avulsions and reduce LH area.

Methods: We carried out a planned secondary analysis from a randomized controlled study. Primiparous women (n=175) giving birth vaginally were included 6 weeks postpartum, stratified on complete LA avulsion, and thereafter randomized to PFMT or control. The training participants (n=87) attended a supervised PFMT class once a week and performed home-based PFMT daily for 16 weeks. The control participants (n=88) received no intervention. Presence of complete LA avulsion, LH area at rest, maximal contraction, and maximal Valsalva maneuver were assessed by transperineal ultrasound. Between-group comparisons were analyzed by analysis of covariance for continuous data, and relative risk (RR) for categorical data.

Results: Six months postpartum, the number of women who had complete LA avulsion was reduced from 27 to 14 within the PFMT group (44% reduction) and from 28 to 17 within the control group (39% reduction). The between-group difference was not significant, RR 0.85 (95% CI 0.53 to 1.37). Further, no significant between-group differences were found for LH area at rest, during contraction, or Valsalva.

Conclusions: Supervised PFMT class combined with home exercise early postpartum did not reduce the presence of complete LA avulsion or LH area more than natural remission.

Keywords: Levator ani muscle avulsion; Levator hiatus area; Physical therapy; Postpartum pelvic floor muscle training; Vaginal delivery.

Fig. 1

Tomographic ultrasound imaging of the levator ani (LA) muscle after vaginal delivery in the axial plane of minimal hiatal dimensions in render mode [19]. Normal muscle insertion of the LA muscle is marked by the dotted circle. Abnormal LA muscle insertion is marked by an arrow. Image A shows an intact LA muscle, B shows a major LA tear unilaterally, and C shows a major LA tear bilaterally. SP symphysis pubis, U urethra, V vagina, R rectum

Fig. 2

The levator ani muscle seen between the solid and dotted line in the axial plane of minimal hiatal dimensions in render mode [19]. The muscle inserts on the os pubis bilaterally of the symphysis pubis (SP) and forms a “U-shaped” sling around the urethra (U), vagina (V), and rectum (R), and hence border the levator hiatus area (seen within the dotted line)

Fig. 3

Flowchart of participants through each stage of the randomized trial. This flowchart has previously been published [16]