22. The Normal Mechanisms of Labour

  1. D. Keith Edmonds FRCOG, RRACOG
  1. Andrés López Bernal MD, DPhil (Oxon)1 and
  2. Errol R. Norwitz MD, DPhil (Oxon)2

Published Online: 5 JAN 2012

DOI: 10.1002/9781119979449.ch22

Dewhurst's Textbook of Obstetrics & Gynaecology, Eighth Edition

Dewhurst's Textbook of Obstetrics & Gynaecology, Eighth Edition

How to Cite

López Bernal, A. and Norwitz, E. R. (2012) The Normal Mechanisms of Labour, in Dewhurst's Textbook of Obstetrics & Gynaecology, Eighth Edition (ed D. K. Edmonds), Wiley-Blackwell, Oxford, UK. doi: 10.1002/9781119979449.ch22

Editor Information

  1. Queen Charlotte's & Chelsea Hospital, London, UK

Author Information

  1. 1

    School of Clinical Sciences, University of Bristol, and St Michael's Hospital, Bristol, UK

  2. 2

    Department of Obstetrics, Gynecology and Reproductive Sciences Yale, New Haven Hospital, New Haven, CT, USA

Publication History

  1. Published Online: 5 JAN 2012
  2. Published Print: 10 JAN 2012

ISBN Information

Print ISBN: 9780470654576

Online ISBN: 9781119979449



  • labour;
  • parturition;
  • human;
  • pregnancy;
  • preterm birth;
  • fetus;
  • uterus;
  • contractions;
  • prostaglandins;
  • oxytocin


Labour is the physiological process by which the products of conception are passed from the uterus to the outside world, and is common to all mammalian viviparous species. The timely onset of labour is a critical determinant of perinatal outcome. Both preterm birth (defined as delivery prior to 37 weeks) and post-term pregnancy (continuation beyond 42 weeks of gestation) are associated with increased perinatal morbidity and mortality. The chapter summarizes the current state of knowledge on the endocrine, genetic, biochemical and molecular mechanisms responsible for the onset of labour at term and for the safe and timely delivery of the fetus. The clinical management of normal labour and birth is also reviewed.