Quantification of friction force reduction induced by obstetric gels

  • Robert RienerEmail author
  • Kerstin Leypold
  • Andreas Brunschweiler
  • Andreas Schaub
  • Ulrich Bleul
  • Peter Wolf
Original Article


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.


Lubrication Mechanical testing Movement speed Dwell time 



The authors wish to thank Giochen Bearth, abattoir’s veterinary inspection service for providing fresh samples. The authors are further grateful to Mario Sikic and Diego Stutzer from the SMS-Lab and Rainer Burgkart from the University Hospital rechts der Isar, TU München, for their advice on this research.


  1. 1.
    Ahlers D (1993) Rechtsfragen in der Geburtshilfe. In: Richter/Goetze Tiergeburtshilfe. Paul Parey, BerlinGoogle Scholar
  2. 2.
    Albers LL, Sedler KD, Bedrick EJ, Teaf D, Peralta P (2005) Midwifery care measures in second stage of labor and reduction of genital tract trauma at birth: a randomized trial. J Midwifery Womens Health 50:365–372. doi: 10.1016/j.jmwh.2005.05.012 CrossRefGoogle Scholar
  3. 3.
    Brement S, Mossan S, Belery A, Racinet C (2008) Delivery in lateral position: randomized clinical trial comparing the maternal positions in lateral position and dorsal position for the second stage of labour. Gynecol Obstet Fertil 36:119–120. doi: 10.1016/j.gyobfe.2007.10.021 CrossRefGoogle Scholar
  4. 4.
    Cheng YW, Hopkins LM, Caughey AB (2004) How long is too long: does a prolonged second stage of labor in nulliparous women affect maternal and neonatal outcomes? Am J Obstet Gynecol 2004191:933–938. doi: 10.1016/j.ajog.2004.05.044 CrossRefGoogle Scholar
  5. 5.
    Cheng YW, Hopkins LM, Russel KL, Aaron BC (2007) Duration of the second stage of labor in multiparous women: maternal and neonatal outcomes. Am J Obstet Gynecol 196:585–587Google Scholar
  6. 6.
    Donnelly V, Fynes M, Campbell D, Johnson H, O’Connell PR, O’Herlihy C (1998) Obstetric events leading to anal sphincter damage. Obstet Gynecol 92:955–961. doi: 10.1016/S0029-7844(98)00255-5 CrossRefGoogle Scholar
  7. 7.
    Eason E, Labrecque M, Wells G, Feldman P (2000) Preventing perineal trauma during childbirth: a systematic review. Obstet Gynecol 95:464–471. doi: 10.1016/S0029-7844(99)00560-8 CrossRefGoogle Scholar
  8. 8.
    Hofmeyr GJ (2004) Obstructed labor: using better technologies to reduce mortality. Int J Gynaecol Obstet 85(S1):S62–S72. doi: 10.1016/j.ijgo.2004.01.011 CrossRefGoogle Scholar
  9. 9.
    Klingelnerg J (2008) Kegelräder: Grundlagen, Anwendungen. Springer, BerlinGoogle Scholar
  10. 10.
    Leypold K (2008) Experimental investigations on friction and lubrication during delivery. Master thesis, Departement of Medical Engineering, TU MünchenGoogle Scholar
  11. 11.
    Rempen A, Kraus M (1991) Pressures on the fetal head during normal labor. J Perinat Med 19:199–206CrossRefGoogle Scholar
  12. 12.
    Schaub AF, Litschgi M, Hoesli I, Holzgreve W, Bleul U, Geissbühler V (2008) Obstetric gel shortens second stage of labor and prevents perineal trauma in nulliparous women: a randomized controlled trial on labor facilitation. J Perinat Med 36:129–135. doi: 10.1515/JPM.2008.024 CrossRefGoogle Scholar
  13. 13.
    Stamp G, Kruzins G, Crowther C (2001) Perineal massage in labour and prevention of perineal trauma: randomised controlled trial. BMJ 322:1277–1280. doi: 10.1136/bmj.322.7297.1277 CrossRefGoogle Scholar
  14. 14.
    Stewart P, Hillan E, Calder AA (1983) A randomized trial to evaluate the use of a birth chair for delivery. Lancet 1:1296–1299. doi: 10.1016/S0140-6736(83)92412-1 CrossRefGoogle Scholar
  15. 15.
    Turner MJ, Romney NL, Webb JB, Gordon H (1986) The birthing chair: an obstetric hazard? J Obstet Gynaecol 6:232–235. doi: 10.3109/01443618609079206 CrossRefGoogle Scholar
  16. 16.
    Waldenstrom U, Gottvall K (1991) A randomized trial of birthing stool of conventional semirecumbent position for second stage of labor. Birth 18:5–10. doi: 10.1111/j.1523-536X.1991.tb00045.x CrossRefGoogle Scholar

Copyright information

© International Federation for Medical and Biological Engineering 2009

Authors and Affiliations

  • Robert Riener
    • 1
    Email author
  • Kerstin Leypold
    • 1
  • Andreas Brunschweiler
    • 1
  • Andreas Schaub
    • 2
  • Ulrich Bleul
    • 3
  • Peter Wolf
    • 1
  1. 1.Department of Mechanical and Process EngineeringETH ZurichZurichSwitzerland
  2. 2.Happy Child Birth Holding AGBaselSwitzerland
  3. 3.Clinic of Reproductive MedicineVetsuisse-Faculty University ZurichZurichSwitzerland

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