New approaches for assessing childbirth positions

Abstract

Background: An overview of labor based only on epidemiological data cannot identify or explain the mechanisms involved in childbirth. Data about the position that women should take in giving birth are discordant. None of the studies of birth positions adequately define or describe them or their biomechanical impact (pelvic orientation, position of the back). The measurement of the effect of one position relative to that of another requires precise definitions of each position and of their maternal biomechanical consequences, as well as safe measurement methods.

Methodology: We have developed a system to analyze the position of labor by quantifying the posture of the woman's body parts (including thighs, trunk, and pelvis), using an optoelectronic motion capture device (Vicon™, Oxford Metrics) widely used in human movement analysis and a system for measuring the lumbar curve (Epionics spine system). A specific body model has also been created to conduct this biomechanical analysis, which is based on external markers. With this methodology and model, it should be possible to define: (1) the hip joint angles (flexion/extension, abduction/adduction, internal/external rotation); (2) the ante/retroversion of the pelvis; (3) the lumbar curve.

Discussion: This methodology could become a reference for assessing delivery postures, one that makes it possible to describe the relation between the postures used in the delivery room and their impact on the pelvis and the spine in an integrated and comprehensive model.

Trial registration: No. Eudract 2013-A01203-42.

Keywords: Assessment; Biomechanics; Delivery; Lumbar curve; Motion capture; Obstetrical; Pelvis; Position.