This prospective observational cohort study aims to investigate the association between maternal musculoskeletal factors of the hip, lumbopelvic, abdominal, and pelvic floor regions and childbirth outcomes, as well as their consequences on pelvic floor function during the postpartum period. A total of 376 pregnant women will be recruited at 36 weeks of gestation and followed until 12 weeks postpartum. Musculoskeletal assessments will include hip range of motion, lumbopelvic mobility, abdominal muscle function, and pelvic floor strength and morphology. Obstetric outcomes such as mode of delivery and perineal trauma will be recorded after childbirth. The study will analyze whether maternal musculoskeletal function during late pregnancy is associated with delivery mode and pelvic floor dysfunction in the postpartum period.

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.

Inclusion Criteria:

• Pregnant women aged 18 years or older
• Singleton pregnancy
• Gestational age of 36 weeks at the time of the baseline assessment
• Receiving prenatal care in primary healthcare centers of Zaragoza (Spain)
• Ability to understand study procedures and provide written informed consent

Exclusion Criteria:

• Multiple pregnancy
• High-risk pregnancy conditions that may affect labor progression or maternal musculoskeletal assessment (e.g., severe obstetric complications requiring planned cesarean section)
• Previous pelvic floor surgery
• Neurological or musculoskeletal disorders affecting the lumbopelvic or pelvic floor region
• Inability to complete the assessment protocol or questionnaires

The study population will consist of pregnant women receiving prenatal care in primary healthcare centers of the Zaragoza II Health Sector (Zaragoza, Spain). Participants will be recruited during routine antenatal care visits at approximately 36 weeks of gestation. Women who meet the eligibility criteria and provide informed consent will undergo musculoskeletal assessment during late pregnancy and will be followed until 12 weeks postpartum.

De-identified individual participant data underlying the results reported in publications derived from this study may be made available upon reasonable request to the principal investigator. Data sharing will be considered for researchers with a methodologically sound proposal and in accordance with institutional policies, ethical approval, and applicable data protection regulations.