Abstract：Objective To analyze the postpartum exercise self-efficacy trajectory categories in pelvic floor muscle and their influencing factors among advanced maternal age, so as to provide evidence for improving pelvic floor muscle function among advanced maternal age. Methods From September 2021 to September 2025, advanced maternal age aged ≥35 years who delivered at the First Affiliated Hospital of Xinjiang Medical University were recruited using convenience sampling. Baseline information was collected through a questionnaire survey within one week postpartum. Family support was assessed using the Chinese version of the Family Functioning Assessment Scale. Postpartum exercises self-efficacy in pelvic floor muscle was assessed using the Chinese version of the Broome Pelvic Muscle Self-Efficacy Scale (BPMSES). A latent class growth model (LCGM) was established based on BPMSES scores at 1 week, 1, 3, 6 and 12 months postpartum to identify postpartum exercise self-efficacy trajectory categories in pelvic floor muscle. Influencing factors affecting postpartum exercise self-efficacy trajectory categories in pelvic floor muscle were analyzed using a multinomial logistic regression model. Results A total of 90 advanced maternal age were surveyed, including 62 (68.89%) aged 35-<40 years. The LCGM identified three trajectory categories of postpartum exercise self-efficacy in pelvic floor muscle, defined according to their changing patterns as the stable group, slow-increase group and rapid-increase group, comprising 17 (18.89%), 45 (50.00%) and 28 (31.11%) women, respectively. Multinomial logistic regression analysis showed that, compared with the stable group, advanced maternal age with a college and above education level (college, OR=3.214, 3.658; bachelor, OR=3.862, 4.215), received postpartum guidance on pelvic floor muscle exercises (OR=3.426, 3.985), and with moderate and above levels of family support (moderate, OR=2.542, 2.876; high, OR=3.118, 3.524) had higher odds of being classified into the slow-increase or rapid-increase group. In contrast, advanced maternal age with postpartum complications (OR=0.356, 0.312), lower infant birth weight (OR=0.412, 0.385) or higher infant birth weight (OR=0.376, 0.342) were associated with lower odds of being classified into the slow-increase or rapid-increase group. Conclusions Postpartum exercise self-efficacy trajectory categories in pelvic floor muscle among advanced maternal age were classified into three distinct trajectories: stable group, slow-increase group and rapid-increase group. Educational level, postpartum complications, postpartum guidance on pelvic floor muscle exercises, infant birth weight and levels of family support were associated with trajectory categories.
