Original Article

Medical & Biological Engineering & Computing

, Volume 47, Issue 6, pp 617-623

Quantification of friction force reduction induced by obstetric gels

  • Robert RienerAffiliated withDepartment of Mechanical and Process Engineering, ETH Zurich Email author 
  • , Kerstin LeypoldAffiliated withDepartment of Mechanical and Process Engineering, ETH Zurich
  • , Andreas BrunschweilerAffiliated withDepartment of Mechanical and Process Engineering, ETH Zurich
  • , Andreas SchaubAffiliated withHappy Child Birth Holding AG
  • , Ulrich BleulAffiliated withClinic of Reproductive Medicine, Vetsuisse-Faculty University Zurich
  • , Peter WolfAffiliated withDepartment of Mechanical and Process Engineering, ETH Zurich

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Abstract

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.

Keywords

Lubrication Mechanical testing Movement speed Dwell time