Normal labour and birth

It is 02:40 and you are asked to review a first-time mother who has been 6 cm for three hours. Everyone in the room wants a number from you. The trap is that the number they want — 1 cm per hour — was never physiology, and the woman in front of you may be entirely normal.^[2][4]

This topic is the baseline against which every intrapartum decision is measured. You cannot diagnose slow progress, justify an induction or defend a caesarean unless you can say, precisely and with a source, what normal looks like.^[1][18]

Overview and definition

Labour is regular painful uterine contractions producing progressive cervical effacement and dilatation, ending in birth of the baby and placenta. The definition matters less than where you draw the line between latent and active, because that line decides who gets admitted, examined, augmented and operated on.^[1][18]

RANZCOG C-Obs 31 adopts the World Health Organization definitions outright, and you should quote them in that form: ^[1][18]

• Latent phase — painful contractions with variable cervical change including some effacement, and slower dilatation up to 4 cm, in both first and subsequent labours.^[1]
• Active (established) phase — regular painful contractions, substantial effacement and more rapid dilatation from 5 cm to full dilatation, in both first and subsequent labours.^[1][2]
• Slow labour — the RANZCOG consensus definition: less than a 2 cm increase in cervical dilatation over a 4-hour period from 5 cm. Descent, rotation and application of the head all inform that judgement.^[18]

"Normal birth" is a label you can only apply looking backwards. A labour that needed a syntocinon infusion, an epidural and an episiotomy is not made normal by ending in a vaginal birth — and a labour that took 20 hours with nothing but support and water is not made abnormal by the clock.^[1][13]

References20ShowHide

1. [1]Oladapo OT, Tunçalp Ö, Bonet M, et al. WHO model of intrapartum care for a positive childbirth experience: transforming care of women and babies for improved health and wellbeing BJOG, 2018.PMID 29637727
2. [2]Oladapo OT, Diaz V, Bonet M, et al. Cervical dilatation patterns of 'low-risk' women with spontaneous labour and normal perinatal outcomes: a systematic review BJOG, 2018.PMID 28892266
3. [3]Abalos E, Oladapo OT, Chamillard M, et al. Duration of spontaneous labour in 'low-risk' women with 'normal' perinatal outcomes: A systematic review Eur J Obstet Gynecol Reprod Biol, 2018.PMID 29518643
4. [4]Zhang J, Landy HJ, Ware Branch D, et al. Contemporary patterns of spontaneous labor with normal neonatal outcomes Obstet Gynecol, 2010.PMID 21099592
5. [5]Lavender T, Cuthbert A, Smyth RM Effect of partograph use on outcomes for women in spontaneous labour at term and their babies Cochrane Database Syst Rev, 2018.PMID 30080256
6. [6]Ubom AE, Nieto-Calvache AJ, Malel ZJ, et al. FIGO position statement on the use of the WHO labor care guide versus the partograph Int J Gynaecol Obstet, 2025.PMID 40285693
7. [7]Vogel JP, Comrie-Thomson L, Pingray V, et al. Usability, acceptability, and feasibility of the World Health Organization Labour Care Guide: A mixed-methods, multicountry evaluation Birth, 2021.PMID 33225484
8. [8]Begley CM, Gyte GM, Devane D, et al. Active versus expectant management for women in the third stage of labour Cochrane Database Syst Rev, 2019.PMID 30754073
9. [9]Gallos ID, Yunas I, Devall AJ, et al. Uterotonic agents for preventing postpartum haemorrhage: a network meta-analysis Cochrane Database Syst Rev, 2025.PMID 40237648
10. [10]McDonald SJ, Middleton P, Dowswell T, et al. Effect of timing of umbilical cord clamping of term infants on maternal and neonatal outcomes Cochrane Database Syst Rev, 2013.PMID 23843134
11. [11]Rouse DJ, Weiner SJ, Bloom SL, et al. Second-stage labor duration in nulliparous women: relationship to maternal and perinatal outcomes Am J Obstet Gynecol, 2009.PMID 19788967
12. [12]Cahill AG, Srinivas SK, Tita ATN, et al. Effect of Immediate vs Delayed Pushing on Rates of Spontaneous Vaginal Delivery Among Nulliparous Women Receiving Neuraxial Analgesia: A Randomized Clinical Trial JAMA, 2018.PMID 30304425
13. [13]Bohren MA, Hofmeyr GJ, Sakala C, et al. Continuous support for women during childbirth Cochrane Database Syst Rev, 2017.PMID 28681500
14. [14]Lawrence A, Lewis L, Hofmeyr GJ, et al. Maternal positions and mobility during first stage labour Cochrane Database Syst Rev, 2013.PMID 24105444
15. [15]Moore ER, Brimdyr K, Blair A, et al. Immediate or early skin-to-skin contact for mothers and their healthy newborn infants Cochrane Database Syst Rev, 2025.PMID 41120189
16. [16]Alfirevic Z, Devane D, Gyte GM, et al. Continuous cardiotocography (CTG) as a form of electronic fetal monitoring (EFM) for fetal assessment during labour Cochrane Database Syst Rev, 2017.PMID 28157275
17. [17]Smyth RM, Markham C, Dowswell T Amniotomy for shortening spontaneous labour Cochrane Database Syst Rev, 2013.PMID 23780653
18. [18]Abalos E, Chamillard M, Díaz V, et al. Progression of the first stage of spontaneous labour Best Pract Res Clin Obstet Gynaecol, 2020.PMID 32247770
19. [19]Laughon SK, Berghella V, Reddy UM, et al. Neonatal and maternal outcomes with prolonged second stage of labor Obstet Gynecol, 2014.PMID 24901265
20. [20]Macones GA, Hankins GD, Spong CY, et al. The 2008 National Institute of Child Health and Human Development workshop report on electronic fetal monitoring: update on definitions, interpretation, and research guidelines Obstet Gynecol, 2008.PMID 18757666