Pelvic floor muscle training (PFMT) reduces the symptoms in women with pelvic floor dysfunction (PFD); however, the optimal initial timing for secondary prevention of PFD by PFMT is not clear. To identify the optimal timing in Asian primiparas with vaginal delivery, bladder neck descent (BND), levator hiatus areas, and levator hiatus distensibility and contractility were assessed in 26 nulliparous women at 36 weeks of gestation and at 2, 4, 6, and 12 weeks postpartum. We found that BND increased significantly from 2 weeks onwards until 6 weeks postpartum (p = 0.004); the levator hiatus area at rest and contraction both showed the largest value at 2 weeks postpartum (p = 0.005 and p < 0.005 respectively), followed by a continuous decrease; the hiatus area during Valsalva manoeuvre, and the levator hiatus distensibility and contractility showed the lowest value at 2 weeks postpartum, followed by a continuous increase; the changes in BND showed no correlation with the changes in distensibility or hiatus area during Valsalva manoeuvre (p = 0.073 and 0.590 respectively). In Asian primiparas with vaginal delivery, the recovery of levator hiatus and bladder neck mobility begins at 2 and 6 weeks, respectively. This information could be useful in defining the best time to begin PFMT for secondary prevention of postpartum PFD in Asian primiparous women.IMPACT STATEMENTWhat is already known on this subject? Pelvic floor muscle training (PFMT) helps to reduce symptoms of pelvic floor dysfunction (PFD), however, there are no clear time strategies for the secondary prevention of PFD by PFMT in Asian primiparas with vaginal delivery.What do the results of this study add? This study was the first longitudinal study in Asian primipara to investigate the natural regeneration of pelvic floor functions in the early postpartum period by intensively monitoring the bladder neck mobility and levator hiatus dimensions at multiple time points. We found that bladder neck descent (BND) increased significantly from 2 weeks onwards until 6 weeks postpartum; the levator hiatus area at rest and contraction both showed the largest value at 2 weeks postpartum, followed by a continuous decrease; the hiatus area during Valsalva manoeuvre, and the levator hiatus distensibility and contractility showed the lowest value at 2 weeks postpartum, followed by a continuous increase; the changes in BND showed no correlation with the changes in distensibility or hiatus area during Valsalva manoeuvre.What are the implications of these findings for clinical practice and/or further research? Our study suggested that in Asian primipara, the recovery of bladder neck mobility after vaginal delivery begins at 6 weeks postpartum, while the levator hiatus muscle begins to recover within the first 2 weeks postpartum. Therefore, it could be useful in deciding the best time to start PFMT for secondary prevention of postpartum PFD in Asian primiparous women.
Keywords: Asian primipara; Pelvic floor ultrasound; bladder neck descent; levator hiatus dimension; pelvic floor dysfunction.