Pelvic floor muscles are subject to considerable stretching during vaginal birth. In 13-36% of women, stretching results in avulsion injury whereby the puborectalis muscle disconnects from its insertion points on the pubis bone. Until now, few studies have investigated the effect of this lesion on pelvic floor muscles in the early postpartum period.

The primary aim of this study was to compare pelvic floor muscle morphometry and function in primiparous women with and without puborectalis avulsion in the early postpartum period. Our secondary objective was to compare the 2 groups for pelvic floor disorders and impact on quality of life.

In all, 52 primiparous women diagnosed with (n = 22) or without (n = 30) puborectalis avulsion injury were assessed at 3 months postpartum. Pelvic floor muscle morphometry was evaluated with 3-/4-dimensional transperineal ultrasound at rest, maximal contraction, and Valsalva maneuver. Different parameters were measured in the midsagittal and axial planes: bladder neck position, levator plate angle, anorectal angle, and levator hiatus dimensions. The dynamometric speculum was used to assess pelvic floor muscle function including: passive properties (passive forces and stiffness) during dynamic stretches, maximal strength, speed of contraction, and endurance. Pelvic floor disorder–related symptoms (eg, urinary incontinence, vaginal and bowel symptoms) and impact on quality of life were evaluated with the International Consultation on Incontinence Questionnaire and the Pelvic Floor Impact Questionnaire-Short Form. Pelvic Organ Prolapse Quantification was also assessed.

In comparison to women without avulsion, women with avulsion presented an enlarged hiatus area at rest, maximal contraction, and Valsalva maneuver (P ≤ .013) and all other ultrasound parameters were found to be significantly altered during maximal contraction (P ≤ .014). They showed lower passive forces at maximal and 20-mm vaginal apertures as well as lower stiffness at 20-mm aperture (P ≤ .048). Significantly lower strength, speed of contraction, and endurance were also found in women with avulsion (P ≤ .005). They also presented more urinary incontinence symptoms (P = .040) whereas vaginal and bowel symptoms were found to be similar in the 2 groups. Pelvic Organ Prolapse Quantification revealed greater anterior compartment descent in women with avulsion (P ≤ .010). The impact of pelvic floor disorders on quality of life was found to be significantly higher in women with avulsion (P = .038).

This study confirms that pelvic floor muscle morphometry and function are impaired in primiparous women with puborectalis avulsion in the early postpartum period. Moreover, it highlights specific muscle parameters that are altered such as passive properties, strength, speed of contraction, and endurance.