Effects of Functional Magnetic Stimulation Combined with Pelvic Floor Muscle Training on Cerebral Hemodynamics and Brain Functional Connectivity in Women with Postpartum Pelvic Floor Dysfunction: A Randomized Controlled Trial.

Background: The central and peripheral effects of pelvic floor muscle training (PFMT) combined with functional magnetic stimulation (FMS) on postpartum pelvic floor dysfunction (PFD) remain unknown. This study aimed to compare the efficacy of PFMT + FMS versus PFMT + sham FMS on postpartum PFD and to explore the underlying central nervous mechanisms. Methods: Sixty women with postpartum PFD were randomly assigned to receive 8 weeks of PFMT + FMS or PFMT + sham FMS. Women in both groups were assessed using pelvic floor surface electromyography, transperineal four-dimensional ultrasound, and functional near-infrared spectroscopy at baseline and after 8 weeks of treatment. The primary outcome was to compare the improvements in muscle strength between the two groups. T-tests and Pearson correlation analyses were employed for statistical analysis. Results: After 8 weeks, compared with the sham stimulation group, the active stimulation group exhibited greater improvements in anterior (p = 0.048) and posterior (p = 0.047) resting muscle tone, fast-twitch [mean difference = 7.52 μV (95% CI, 4.36 to 10.68)] and slow-twitch muscle strength [8.56 μV (4.77 to 12.34)], and slow-twitch muscle endurance [7.13 μV (3.51 to 10.76)] (p < 0.001), with more pronounced improvements across all ultrasound metrics. Concurrently, oxyhemoglobin concentrations in sensorimotor cortex (SMC), supplementary motor area, and premotor cortex (PMC) were elevated in the active stimulation group during Kegel exercises. Functional connectivity increased between the ipsilateral PMC and SMC and between the bilateral SMC, with a rising trend in brain network connectivity efficiency [0.0639 (0.0136 to 0.1142), p = 0.015]. These reflected enhanced recruitment of the central nervous system and more efficient coordination of motor control strategies. Moreover, correlation analysis revealed a positive correlation between improvements in pelvic floor muscle function and changes in brain network efficiency. Conclusion: Compared to PFMT alone, combined treatment demonstrates superior efficacy in improving pelvic floor muscle function and anatomical structure in women with postpartum PFD, centrally characterized by increased motor cortex activation and brain network connectivity efficiency. Trial Registration: Chinese Clinical Trial Registry, ChiCTR2400084678. Registered 22 May 2024, https://www.chictr.org.cn/.