Abstract
BACKGROUND: Pregnancy-related anatomical and hormonal changes, including increased relaxin levels, may cause ligamentous laxity and joint hypermobility, while also contributing to decreased overall body mobility, potentially affecting functional stability. Pilates, focusing on core strength and postural control, is recommended during pregnancy, but its effects on ligamentous laxity and joint hypermobility have not been tested in a randomized controlled trial. This study aimed to investigate the effectiveness of a prenatal Pilates program on ligamentous laxity and joint hypermobility in pregnant women. METHODS: In this prospectively registered, dual-center randomized controlled trial (ClinicalTrials.gov: NCT06684002), 42 healthy primiparous women at 14-16 weeks' gestation were randomized to an 8-week structured prenatal Pilates program (n = 21) or standard prenatal care without exercise (n = 21). The intervention was delivered by the same certified physiotherapist at both centers to ensure consistency. Outcomes included anterior cruciate ligamentous laxity measured with the GNRB arthrometer, generalized joint hypermobility using the Beighton score, and activity limitations due to pelvic girdle pain assessed by the Pelvic Girdle Questionnaire, evaluated at baseline, 4 weeks, and 8 weeks. RESULTS: Participants in the Pilates group showed no significant changes in ligamentous laxity and joint hypermobility and reported minimal activity limitations throughout the intervention (p > 0.05). In contrast, the control group demonstrated significant deterioration across all outcomes (p < 0.05). After 8 weeks, the Pilates group demonstrated significant improvements compared to the control group, with medium effect sizes for ligamentous laxity (p < 0.05, ηp² ≥ 0.06), a small effect size for joint hypermobility (p = 0.017, ηp² = 0.039), and a large effect size for activity limitations due to pelvic girdle pain (p = 0.021, ηp² = 0.317). CONCLUSIONS: An 8-week structured prenatal Pilates program appears to effectively prevent the progression of ligamentous laxity and joint hypermobility while reducing activity limitations associated with pelvic girdle pain, supporting its integration into routine prenatal care to enhance maternal musculoskeletal stability, functional capacity, and quality of life during pregnancy. TRIAL REGISTRATION: This study is registered on ClinicalTrials.gov with the identifier NCT06684002, registration date November 9, 2024.