Maternal Musculoskeletal Factors of the Hip, Lumbopelvic, Abdominal and Pelvic Floor Regions and Their Association With Mode of Delivery and Postpartum Pelvic Floor Dysfunction

Childbirth represents a major biomechanical and physiological challenge for the maternal pelvic floor. During vaginal delivery, the pelvic floor muscles and connective tissues undergo substantial mechanical strain, which may result in perineal trauma and contribute to the development of pelvic floor disorders such as urinary incontinence, anal incontinence, pelvic organ prolapse, dyspareunia, and chronic pelvic pain during the postpartum period. Identifying modifiable factors that may influence childbirth outcomes is therefore essential for improving maternal health.

Recent biomechanical models of childbirth suggest that maternal musculoskeletal function may play a relevant role in the progression of labor and in the mechanical stress experienced by pelvic floor structures. Hip mobility, pelvic and lumbar movement, abdominal muscle activation, and pelvic floor muscle strength may influence pelvic biomechanics during labor, fetal descent, and the efficiency of maternal pushing efforts. However, the relationship between maternal musculoskeletal status during pregnancy and obstetric outcomes remains poorly understood.

The aim of this study is to analyze the association between maternal musculoskeletal factors of the hip, lumbopelvic, abdominal, and pelvic floor regions during late pregnancy and the characteristics of childbirth, as well as their potential impact on pelvic floor dysfunction during the postpartum period.

This study is designed as a prospective observational cohort study. Pregnant women will be recruited at 36 weeks of gestation from primary healthcare centers in Zaragoza (Spain). Participants will undergo three assessment time points: baseline evaluation at 36 weeks of gestation (T0), follow-up after childbirth to collect obstetric outcomes (T1), and a postpartum evaluation at 12 weeks after delivery (T2).

At baseline and postpartum follow-up, participants will undergo a comprehensive musculoskeletal assessment including hip range of motion and muscle length tests, lumbopelvic mobility and sacral inclination measurements, ultrasound assessment of abdominal muscles and inter-rectus distance, and pelvic floor evaluation including pelvic floor muscle strength, perineal body length, and transperineal ultrasound assessment of the puborectalis muscle. Self-reported questionnaires will also be used to assess lumbopelvic disability and pelvic floor-related symptoms.

Obstetric variables recorded after delivery will include mode of delivery, perineal trauma, obstetric interventions, labor characteristics, fetal weight, and maternal satisfaction with childbirth.

The primary obstetric outcome will be non-eutocic delivery, defined as instrumental delivery or cesarean section. The primary perineal outcome will be clinically significant perineal trauma, defined as episiotomy or spontaneous perineal tear of grade II or higher among women who experience vaginal delivery.

Statistical analyses will include descriptive statistics, bivariate comparisons between groups, and multivariable logistic regression models to evaluate the association between predefined musculoskeletal predictors and obstetric outcomes. Additional regression models will explore the relationship between prenatal musculoskeletal factors, childbirth characteristics, and pelvic floor dysfunction in the postpartum period.

The results of this study may contribute to identifying maternal musculoskeletal factors associated with childbirth outcomes and postpartum pelvic floor health, potentially supporting the development of preventive physiotherapy strategies during pregnancy.