Medical & Biological Engineering & Computing

, Volume 47, Issue 6, pp 617–623

Quantification of friction force reduction induced by obstetric gels


    • Department of Mechanical and Process EngineeringETH Zurich
  • Kerstin Leypold
    • Department of Mechanical and Process EngineeringETH Zurich
  • Andreas Brunschweiler
    • Department of Mechanical and Process EngineeringETH Zurich
  • Andreas Schaub
    • Happy Child Birth Holding AG
  • Ulrich Bleul
    • Clinic of Reproductive MedicineVetsuisse-Faculty University Zurich
  • Peter Wolf
    • Department of Mechanical and Process EngineeringETH Zurich
Original Article

DOI: 10.1007/s11517-009-0460-1

Cite this article as:
Riener, R., Leypold, K., Brunschweiler, A. et al. Med Biol Eng Comput (2009) 47: 617. doi:10.1007/s11517-009-0460-1


The objective of this study was to quantify the reduction of friction forces by obstetric gels aimed to facilitate human childbirth. Lubricants, two obstetric gels with different viscosities and distilled water, were applied to a porcine model under mechanical conditions comparable to human childbirth. In tests with higher movement speeds of the skin relative to the birth canal, both obstetric gels significantly reduced dynamic friction forces by 30–40% in comparison to distilled water. At the lowest movement speed, only the more viscous gel reduced dynamic friction force significantly. In tests modifying the dwell time before a movement was initiated, static friction forces of trials with highly viscous gel were generally lower than those with distilled water. The performed biomechanical tests support the recommendation of using obstetric gels during human childbirth. Using the presented test apparatus may reduce the amount of clinical testing required to optimize gel formulation.


LubricationMechanical testingMovement speedDwell time

Copyright information

© International Federation for Medical and Biological Engineering 2009