Clinical overview
Labour is the physiological process by which the products of conception are expelled from the uterus after the age of viability. "Normal labour" is the benchmark against which every deviation is measured: spontaneous in onset at term (≥37 completed weeks), with a singleton fetus in a cephalic (vertex) presentation, progressing without intervention to a spontaneous vaginal birth of a healthy mother and baby. Most of obstetrics is, in effect, the discipline of recognising when a labour has stopped being normal — so a registrar must hold a precise mental model of what normal looks like, minute to minute, before they can safely call anything abnormal.
Managing normal labour well is deceptively demanding. The clinical imperative is to do less, watchfully — to support the woman, monitor mother and fetus, document progress objectively, and intervene only when there is a defined indication, while never missing the moment a labour tips into obstruction, fetal compromise, or haemorrhage. In South Africa, obstetric haemorrhage, hypertension and the hypoxic-ischaemic consequences of poorly monitored labour remain leading contributors to maternal and perinatal death (Saving Mothers/NCCEMD), and a large share of these deaths are judged avoidable. Disciplined, protocolised intrapartum care — the right level of care, an accurately completed partogram, structured fetal monitoring, and active management of the third stage — is therefore one of the highest-yield things you will ever do. This chapter describes that management; the abnormal labour patterns are covered under Complicated labour.
Core knowledge
Defining and dating labour onset
Labour is the coincidence of regular, painful uterine contractions with progressive cervical change (effacement and dilatation). Contractions alone, however strong, are not labour without cervical change; this distinction underpins the diagnosis of false labour and of the latent phase. A "show" (blood-stained mucus plug) and spontaneous rupture of membranes may herald labour but do not define it.
The stages of labour
Labour is divided into stages, and the first stage into phases. The exact numerical thresholds have shifted in modern guidance away from older Friedman-derived norms, so hedge the numbers and reason from the principle that labour is normal as long as it is progressing and mother and fetus are well.
- First stage — onset of labour to full dilatation (10 cm).
- Latent phase: slow cervical change, classically to around 4–5 cm, often irregular and prolonged. It can last many hours and is not an indication to intervene in a well woman; admitting and "actively managing" the latent phase causes a cascade of unnecessary interventions.
- Active phase: established labour with a faster, more predictable rate of dilatation. Contemporary partogram-based guidance (WHO Labour Care Guide, 2020; SA NDoH Integrated Maternal and Perinatal Care Guideline, NDoH, 2024) recognises that the active phase commonly begins around 5 cm and that the older fixed "1 cm/hour" expectation overdiagnosed dysfunctional labour. A slower-than-textbook but steadily progressing labour in a well mother and fetus is still normal.
- Second stage — full dilatation to delivery of the baby. Subdivided into a passive phase (full dilatation, no urge/involuntary pushing) and an active phase (maternal expulsive effort with the presenting part on the pelvic floor).
- Third stage — delivery of the baby to delivery of the placenta and membranes.
The mechanism of labour ("the seven cardinal movements")
The fetus negotiates the bony pelvis through a stereotyped sequence — engagement, descent, flexion, internal rotation, extension, restitution/external rotation, and expulsion. Understanding this is what lets you interpret abdominal and vaginal findings: a deflexed head presents a larger diameter; failure of internal rotation (e.g. persistent occipito-posterior) lengthens the second stage. The interaction of the three P's — Powers (contractions and maternal effort), Passage (bony pelvis and soft tissues) and Passenger (fetal size, presentation, position, attitude) — frames every assessment of progress. Adequate powers are classically described as 3–4 contractions in 10 minutes, each lasting >40 seconds. The physiology of contractions and fetal oxygen delivery is detailed in Contractions fetal oxygenation.
Levels of care and where normal labour belongs (SA)
Under the SA system, an uncomplicated labour in a low-risk woman can be safely conducted at a midwife-obstetric unit (MOU)/district (level 1) facility. Risk factors identified at booking or in labour (High-risk pregnancy factors) mandate referral to regional (level 2) or tertiary (level 3) care. Knowing the referral criteria — and acting on them early, with the partogram as the trigger — is core SA practice.