Moura Rita, Oliveira Dulce A, Kimmich Nina, Jorge Renato M Natal, Parente Marco P L
Faculty of Engineering of the University of Porto, Rua Dr. Roberto Frias s/n, 4200-465, Porto, Portugal.
Institute of Science and Innovation in Mechanical and Industrial Engineering, Rua Dr. Roberto Frias 400, 4200-465, Porto, Portugal.
Biomech Model Mechanobiol. 2025 Aug;24(4):1435-1446. doi: 10.1007/s10237-025-01977-0. Epub 2025 Jun 19.
Childbirth is a complex process influenced by physiological, mechanical, and hormonal factors. While natural vaginal delivery is the safest, it is not always feasible due to diverse circumstances. In such cases, assisted delivery techniques, such as vacuum-assisted delivery (VAD), may facilitate vaginal birth. However, this technique can be associated with a higher risk of maternal injuries, potentially resulting in long-term conditions such as pelvic organ prolapse or incontinence. This study investigates the biomechanical impact of VAD on maternal tissues, aiming to reduce these risks. A finite element model was developed to simulate VAD, incorporating maternal musculature, a deformable fetal head, and a vacuum cup. Twelve simulations were conducted, varying contraction durations, resting intervals, and the number of pulls required for fetal extraction. Results revealed that prolonged contraction durations, coupled with extended resting intervals, lead to a reduction in pelvic floor stress. Elevated stress levels were observed when fetal extraction involved two pulls, with an 8.43% decrease in maximum stress from two pulls to four. The peak stress recorded was 0.81 MPa during a 60-second contraction, followed by a 60-second rest period. These findings indicate that longer maneuvers may reduce trauma, as extended pulls allow muscles more time to relax and recover during both contraction and rest phases. Furthermore, an increased number of pulls extends the duration of the maneuver, facilitating fetal rotation and improved adjustment to the birth canal. This study offers crucial insights into the biomechanics of childbirth, providing clinicians with valuable information to enhance maternal outcomes and refine assisted delivery techniques.
分娩是一个受生理、机械和激素因素影响的复杂过程。虽然自然阴道分娩是最安全的，但由于各种情况，它并不总是可行的。在这种情况下，辅助分娩技术，如真空辅助分娩（VAD），可能有助于阴道分娩。然而，这种技术可能与产妇受伤的风险较高相关，可能导致诸如盆腔器官脱垂或尿失禁等长期病症。本研究调查了VAD对产妇组织的生物力学影响，旨在降低这些风险。开发了一个有限元模型来模拟VAD，纳入了产妇肌肉组织、可变形的胎儿头部和一个吸杯。进行了12次模拟，改变了收缩持续时间、休息间隔以及胎儿娩出所需的牵拉次数。结果显示，延长收缩持续时间并结合延长休息间隔会导致盆底压力降低。当胎儿娩出涉及两次牵拉时，观察到压力水平升高，从两次牵拉到四次牵拉，最大压力降低了8.43%。在60秒收缩期后接着60秒休息期时记录到的峰值压力为0.81兆帕。这些发现表明，较长时间的操作可能会减少创伤，因为延长的牵拉使肌肉在收缩和休息阶段都有更多时间放松和恢复。此外，增加牵拉次数会延长操作持续时间，有利于胎儿旋转并更好地适应产道。本研究为分娩生物力学提供了关键见解，为临床医生提供了有价值的信息，以改善产妇结局并完善辅助分娩技术。
