Development and validation of a computational model for understanding the effects of an upright birthing position on the female pelvis

A Postural Approach to the Pelvic Diameters of Obstetrics: The Dynamic External Pelvimetry Test

“…It also supports the idea that changing one's posture could lead to a change in pelvic incidence and pelvic tilt and, consequently, to a change in the pelvic space of the birth canal [11][12][13][14]. Loading conditions during dynamic labor positions and increased ligament laxity during pregnancy would expand the pelvis [13]. When the internal diameters change, the external ones also change, and vice-versa, and they could be related to the obstetric outcome.…”

“…Description of the body positions that can be easily assumed by every pregnant woman, with particular regard to the procedure of shifting from a position to another, in observance of the evidence from previous researches [2][3][4][5]11,[13][14].…”

“…The different postural patterns used by women during labor and delivery were analyzed, and the results of the instrumental researches that measured internal pelvic diameters in different body positions were considered [1,[4][5][6][7]11,[13][14]. Afterward, three positions were chosen, differing from each other concerning the degree of flexion-extension of the femoral-acetabular joints and the consequent pelvic rotation ( Figure 5): The three positions were:…”

“…When the internal diameters change, the external ones also change, and vice-versa, and they could be related to the obstetric outcome. Some evidence suggests that the intermediate positions (hands-and-knees position) have a better impact on the dimensions of the diameters of the birth canal than the supine or squat position [11,13]. The dynamic activities and alternative positions are encouraged by midwives during labor and moving may generate greater pelvic mobility than the comparable static posture [14].…”

“…Research with optical-electronic instruments evaluates the change of the position in the space of the sensors placed on the external surface of the body [5,11,[13][14], but some studies show that external landmarks move with body movement due to the soft tissue artifact that would affect external markers located above those points during movement analysis [15]. The human hand is a very precise and reliable sensor; the hand is one of the most complex and beautiful pieces of natural engineering and it allows us to manipulate small objects with great precision [16].…”