Biomechanical evaluation of midwifery tasks and its relationship with the prevalence of musculoskeletal disorders

INTRODUCTION: As an important occupational group in the healthcare system, midwives face various ergonomic risk factors such as musculoskeletal disorders (MSDs) risks. Moreover, an accurate job evaluation can help to design appropriate ergonomic interventions and more accurately estimate the probability of developing MSDs. Therefore, the present study aimed to investigate musculoskeletal discomforts and biomechanical stresses using the Three-Dimensional Static Strength Prediction Program (3DSSPP Ver. 7.1.3) to find the association of these factors with the prevalence of MSDs among midwives. MATERIALS AND METHODS: A total of 91 midwives with at least two years of work experience participated in this cross-sectional descriptive study. All midwifery duties were analyzed using the hierarchical task analysis (HTA) method. Moreover, time analysis was performed for this job, and data were collected using the Nordic Musculoskeletal Questionnaire (NMQ) and body mapping. The 3DSSPP software was used to investigate the forces acting on the lumbar region, and finally, the association of individual characteristics and the forces exerted on the body with MSDs was investigated. RESULTS: According to the results, the highest level of pain and discomfort was related to the back and neck regions. The software analysis of the four major midwifery tasks showed that the highest biomechanical forces were exerted on the L(5)/S(1) disc during lifting the mothers from bed (to help them sit or walk) and breastfeeding training. Accordingly, only in the task of lifting the mothers and helping them to sit or walk, the balance status was inappropriate and critical due to the improper distribution of forces. The analysis of the associations between variables showed that biomechanical forces, age, height, body mass index, and job tenure were among the risk factors affecting MSDs. CONCLUSION: According to the results of this study, MSDs were highly prevalent, especially in the neck and back regions; this can be attributed to the nature of midwifery tasks. The software analysis results of the tasks showed that the biomechanical forces on the spine in each of the tasks can be affected by the weight of the mother, the height of the bed, static posture, and the bending/twisting of the whole body. Compression and shear forces were among the risk factors that can affect MSDs. To prevent MSDs in midwives, it is appropriate to improve the workstations.