Department of Mechanical and Materials Engineering, Queen's University, 130 Stuart Street, Kingston, Ontario K7L 3N6, Canada.
Department of Mechanical and Materials Engineering, Queen's University, 130 Stuart Street, Kingston, Ontario K7L 3N6, Canada.
J Biomech. 2020 Dec 2;113:110114. doi: 10.1016/j.jbiomech.2020.110114. Epub 2020 Nov 9.
Studies have shown that some vertical birthing positions, such as squatting and standing, may influence labour and childbirth. However, a rigorous biomechanical understanding of how different positions affect a woman's pelvis during labour is currently lacking. It was hypothesized that the position of pubic bones is affected in different positions, and thus the pubic symphysis width changes. Therefore, we measured pubic symphysis width on eleven women in their seventh to ninth months of pregnancy in different positions through three-dimensional (3D) reconstruction of pubic symphysis ultrasound images. Positions studies included those used in clinics like supine and lithotomy positions, in addition to squatting and standing, which are recommended by midwives. The results showed that the average superior and inferior pubic symphysis widths in lithotomy, squatting and standing positions were approximately 1 mm larger than those in the supine position. However, no significant difference between lithotomy, squatting and standing positions was found. The results were consistent with those of two comparable studies. A significant difference was only found between standing and squatting, standing and lithotomy in the rotation angle about the medio-lateral axis. The results suggest that positions with thigh hyperflexion and gravity effect make a difference in pubic symphysis width and might have a positive effect in childbirth. However, due to the small sample size, no definite conclusion can be drawn.
研究表明，一些垂直的分娩姿势，如蹲姿和站姿，可能会影响分娩。然而，目前缺乏对不同姿势如何影响分娩时女性骨盆的严格生物力学理解。假设耻骨的位置会在不同的姿势下发生变化，从而导致耻骨联合宽度发生变化。因此，我们通过三维（3D）重建耻骨联合超声图像，对 11 名处于妊娠第 7 至 9 个月的女性在不同姿势下的耻骨联合宽度进行了测量。研究的姿势包括临床中常用的仰卧位和截石位，以及助产士推荐的蹲姿和站姿。结果表明，截石位、蹲姿和站姿时耻骨联合的上、下宽度比仰卧位时大约大 1 毫米。然而，在截石位、蹲姿和站姿之间没有发现显著差异。结果与两项类似的研究一致。仅在关于正中矢状轴的旋转角度方面，发现了站立位和蹲姿之间、站立位和截石位之间的显著差异。这些结果表明，大腿过伸和重力作用的姿势会影响耻骨联合宽度，并可能对分娩产生积极影响。然而，由于样本量较小，不能得出明确的结论。
