Impact of parity on pelvic floor morphology and function: A retrospective study

To analyze the effect of parity on pelvic floor morphology and function during the postpartum period. A total of 971 participants, who attended the Fujian Maternity and Child Health Hospital (Fuzhou, China) between December 2019 and August 2021, were included. All participants were assessed using the modified Oxford scale (MOS), pelvic floor surface electromyography, and 3-dimensional pelvic floor ultrasound to assess pelvic floor morphology and function. Multivariate analysis revealed no differences among primipara, deuteripara, and tertipara in pre-baseline rest, phasic contraction, endurance contraction, post-baseline rest, and MOS, except for tonic contraction (P = .020), the amplitude of which was lower in primipara than in deuteripara in post hoc comparison (P = .008). Differences in bladder neck presentation and bladder neck descent were statistically significant in multivariate analysis (P = .002, P = .001, respectively), with the value of bladder neck presentation in primiparas being greater than that of deuteriparas and tertipara (P = .002, P = .008, respectively), and the value of bladder neck descent was lower than that of deuteripara and tertipara in further post hoc comparisons (P = .002, P = .003, respectively). Functional impairment was not statistically associated with parity according to the MOS score or surface electromyography. However, parity was significantly correlated with descent of the bladder neck, and most of the effects appeared to occur during the first delivery.