title: Quantification of friction force reduction induced by obstetric gels.
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.
authors.affiliation: Department of Mechanical and Process Engineering, ETH Zurich, Switzerland. riener@mavt.ethz.ch
authors.forename: Robert
authors.initials: R
authors.lastname: Riener
authors.forename: Kerstin
authors.initials: K
authors.lastname: Leypold
authors.forename: Andreas
authors.initials: A
authors.lastname: Brunschweiler
authors.forename: Andreas
authors.initials: A
authors.lastname: Schaub
authors.forename: Ulrich
authors.initials: U
authors.lastname: Bleul
authors.forename: Peter
authors.initials: P
authors.lastname: Wolf
mesh_terms: D000818:Animals; D036861:Delivery, Obstetric / Q000379:methods*; D004353:Drug Evaluation, Preclinical / Q000379:methods; D005260:Female; D017276:Friction / Q000187:drug effects; D054327:Lubricants / Q000494:pharmacology*; D023421:Models, Animal; D034421:Sus scrofa; D014622:Vaginal Creams, Foams, and Jellies / Q000494:pharmacology; D014783:Viscosity
chemical_list: D054327:Lubricants; D014622:Vaginal Creams, Foams, and Jellies